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Pulsed Electric Current Dipole/Dipole Interference.
National Technical Information Service (NTIS)
A time-domain analysis of electromagnetic, pulsed electric current dipole/dipole interference is presented. The emitting and suscepting dipoles may be either 'electric dipoles' (short segments of electric current carrying wire) or 'magnetic dipoles' (smal...
D. Quak A. T. de Hoop
Electric dipoles on magnetic monopoles in spin ice.
The close connection of electricity and magnetism is one of the cornerstones of modern physics. This connection has a crucial role from a fundamental point of view and in practical applications, including spintronics and multiferroic materials. A breakthrough was a recent proposal that in magnetic materials called spin ice the elementary excitations have a magnetic charge and behave as magnetic monopoles. I show that, besides magnetic charge, there should be an electric dipole attached to each magnetic monopole. This opens new possibilities to study and control such monopoles using an electric field. Thus, the electric-magnetic analogy goes even further than usually assumed: whereas electrons have electric charge and magnetic dipole (spin), magnetic monopoles in spin ice, while having magnetic charge, also have an electric dipole. PMID:22713746
Khomskii, D I
Colocated Magnetic Loop, Electric Dipole Array Antenna (Preliminary Results).
We present a detailed electromagnetic analysis of an electrically small colocated electric dipole and magnetic loop antenna array. This antenna is the simplest example of the Grimes multipole class of antenna arrays. We have determined that since the inte...
P. L. Overfelt D. R. Bowling D. J. White
New Formulas for HED (Horizontal Electric Dipole), HMD (Horizontal Magnetic Dipole), VED (Vertical Electric Dipole), and VMD (Vertical Magnetic Dipole) Subsurface-to-Subsurface Propagation.
New formulas for the electric and magnetic fields produced by the four elementary dipole antennas have been developed for the subsurface-to-subsurface, subsurface-to-surface, surface-to-subsurface, and surface-to-surface propagation cases. These formulas ...
P. R. Bannister
Quantum phase of an electric dipole moving in a magnetic dipole field
Microsoft Academic Search
It is shown that a neutral particle with an electric dipole moment acquires a quantum phase of Aharonov-Bohm type which is induced by a magnetic dipole field, in addition to the He-McKellar-Wilkens phase which requires a magnetic monopole field. Therefore this phase is measurable in principle. This phase is related to the Casella phase in the sense of the electromagnetic
Tae-Yeon Lee
Measurement of AC electrical characteristics of SSC superconducting dipole magnets
NASA Astrophysics Data System (ADS)
Experiments were conducted to measure the AC electrical characteristics of SSC superconducting dipole magnets over the frequency range of 0.1 Hz to 10 kHz. A magnet equivalent circuit representing the magnet DC inductance, eddy current losses, coil-to-ground, and turn-to-turn capacitance was synthesized from the experimental data. This magnet equivalent circuit can be used to predict the current ripple distribution along the superconducting magnet string and can provide dynamic information for the design of the collider current regulation loop.
Smedley, K. M.; Shafer, R. E.
Atomic electric dipole moment induced by the nuclear electric dipole moment: The magnetic moment effect
SciTech Connect
We have considered a mechanism for inducing a time-reversal violating electric dipole moment (EDM) in atoms through the interaction of a nuclear EDM d{sub N} with the hyperfine interaction, the ''magnetic moment effect''. We have derived the operator for this interaction and presented analytical formulas for the matrix elements between atomic states. Induced EDMs in the diamagnetic atoms {sup 129}Xe, {sup 171}Yb, {sup 199}Hg, {sup 211}Rn, and {sup 225}Ra have been calculated numerically. From the experimental limits on the atomic EDMs of {sup 129}Xe and {sup 199}Hg we have placed the following constraints on the nuclear EDMs, |d{sub N}({sup 129}Xe)|<1.1x10{sup -21}|e|cm and |d{sub N}({sup 199}Hg)|<2.8x10{sup -24}|e|cm.
Porsev, S. G. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Petersburg Nuclear Physics Institute, Gatchina, Leningrad district 188300 (Russian Federation); Ginges, J. S. M.; Flambaum, V. V. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia)
A colocated magnetic loop, electric dipole array antenna (preliminary results)
We present a detailed electromagnetic analysis of an electrically small colocated electric dipole and magnetic loop antenna array. This antenna is the simplest example of the Grimes multipole class of antenna arrays. We have determined that since the interaction term between the two elements disappears from the radial complex power, we were able to set the radial reactance to zero by choosing appropriate current magnitudes and phases on the array elements. By driving the two elements in quadrature, we obtained a much increased radiation intensity and directivity as well as increased radiated power.
Overfelt, P. L.; Bowling, D. R.; White, D. J.
Electrical insulation requirements and test procedures for SSC dipole magnets
The development of the basic requirements for the turn-to-turn, coil-to-coil, and coil-to-ground insulation for SSC dipoles is discussed. The insulation method is also described along with test procedures for verification of insulation integrity. Electrical tests are performed throughout the magnet assembly and fabrication process to verify that coil integrity and insulation quality of the various components and sub-assemblies are within nominal limits. These tests are also required to certify each dipole for SSC acceptance before it is installed in the cryostat and leaves the factory for final installation. The following series of tests, which are conducted at room temperature, are: resistance; inductance and Q''; hypot; impulse; and ratiometer.
Sintchak, G.F.; Cottingham, J.G.; Ganetis, G.L.
Nuclear Magnetic and Electric Dipole Moments of NEON-19.
This thesis presents a detailed discussion of a series of experiments designed to measure the magnetic and electric dipole moments of the (beta)-emitting nucleus ('19)Ne. The ('19)Ne is generated in the reaction ('19)F(p,n)('19)Ne and is polarized by a "Stern-Gerlach" magnet in a rare gas atomic beams machine. The atoms are stored in a cell for many seconds without depolarizing. The parity violating asymmetry in the (beta) angular distribution is used to monitor the nuclear polarization. The polarized atoms are stored in a cell in a uniform magnetic field. The (beta)-asymmetry is monitored by a pair of (beta)-detectors located on either side of the cell. Transitions between the M(,J) = + 1/2 and M(,J) = - 1/2 spin states are induced by an rf field generated by a small Helmholtz coil pair surrounding the cell. Nuclear magnetic resonance lines are observed and the magnetic moment of ('19)Ne measured to be (mu)(('19)Ne) = -1.88542(8)(mu)(,N). A new magnet, cell and detectors were designed to give narrow resonance lines. The equipment is described in detail and several resonance line shapes are discussed. The narrowest resonance line achieved with this system was 0.043 Hz FWHM. This width is primarily due to the ('19)Ne lifetime. Pulsed NMR lineshapes were also observed. The narrow NMR lines observed in the previous experiment were then used as a probe to look for an electric dipole moment (EDM) in ('19)Ne. Any shift in the resonance frequency correlated with changes in an externally applied electric field would be evidence for an EDM. The EDM of the ('19)Ne atom was measured to be (7.2 (+OR-) 6.2) x 10('-22) e-cm. This experiment and possible improvements are discussed in detail.
MacArthur, Duncan Whittemore
Quark electric dipole moment induced by magnetic field in SU(2) gluodynamics
We show that in the external Abelian magnetic field the topological fluctuations of the vacuum of gluodynamics lead to an appearance of the electric dipole moment of quarks in the direction of the magnetic field. The correlation between the electric dipole moment with the chiral density increases with the strength of the field. Thermal fluctuations decrease the correlation between these two quantities.
Luschevskaya, E. V. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); JINR, Dubna, Moscow region, 141980 (Russian Federation); Buividovich, P. V. [JINR, Dubna, Moscow region, 141980 (Russian Federation); ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); Chernodub, M. N. [CNRS, LMPT, Federation Denis Poisson, Universite de Tours, 37200 (France); ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); Polikarpov, M. I. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation)
Electron scattering in graphene by impurities with electric and magnetic dipole moments
The elastic electron scattering by impurities with electric and magnetic dipoles in graphene is studied with the help of Born approximation. Both types of scatterers give the nonzero cross section of backscattering. The scattering by the impurities with electric dipoles is more efficient even comparing to the scattering by the nanomagnets with anomalous magnetic moments. A comparison of the electron scattering transport cross sections by charged impurities and impurities with electric dipole moments shows that they can be comparable. The scattering by the impurities electric dipoles can be important in limiting the electron mobility in graphene along with the Coulomb scattering.
Mal?nev, V. N.; Senbeta, Teshome; Achenefe, Yohannes
Electric charge is a magnetic dipole when placed in a background magnetic field
It is demonstrated, owing to the nonlinearity of QED, that a static charge placed in a strong magnetic field B is a magnetic dipole (besides remaining an electric monopole, as well). Its magnetic moment grows linearly with B as long as the latter remains smaller than the characteristic value of 1.2�1013 G but tends to a constant as B exceeds that value. The force acting on a densely charged object by the dipole magnetic field of a neutron star is estimated.
Adorno, T. C.; Gitman, D. M.; Shabad, A. E.
Spontaneous emission of electric and magnetic dipoles in the vicinity of thin and thick metal
Strong modification of spontaneous emission of Eu3+ ions placed in close vicinity to thin and thick gold and silver films was clearly demonstrated in a microscope setup separately for electric and magnetic dipole transitions. We have shown that the magnetic transition was very sensitive to the thickness of the gold substrate and behaved distinctly different from the electric transition. The observations were described theoretically based on the dyadic Green's function approach for layered media and explained through modified image models for the near and far-field emissions. We established that there exists a "near-field event horizon", which demarcates the distance from the metal at which the dipole emission is taken up exclusively in the near field.
Hussain, R.; Keene, D.; Noginova, N.; Durach, M.
Spontaneous emission of electric and magnetic dipoles in the vicinity of thin and thick metal.
Strong modification of spontaneous emission of Eu(3+) ions placed in close vicinity to thin and thick gold and silver films was clearly demonstrated in a microscope setup separately for electric and magnetic dipole transitions. We have shown that the magnetic transition was very sensitive to the thickness of the gold substrate and behaved distinctly different from the electric transition. The observations were described theoretically based on the dyadic Green's function approach for layered media and explained through modified image models for the near and far-field emissions. We established that there exists a "near-field event horizon", which demarcates the distance from the metal at which the dipole emission is taken up exclusively in the near field. PMID:24718150
Hussain, R; Keene, D; Noginova, N; Durach, M
Electric-dipole-active magnetic resonance in the conical-spin magnet Ba2Mg2Fe12O22
Electric-field (E) drive of magnetic resonance in a solid has been a big challenge in condensed-matter physics and emerging spintronics. We demonstrate the appearance of distinct magnetic excitations driven by the light E component in a hexaferrite Ba2Mg2Fe12O22 . In the conical-spin state even with no spontaneous electric polarization (Ps) , a sharp and intense resonance is observed around 2.8 meV for the light E vector parallel to the magnetic propagation vector in accord with the inelastic neutron scattering spectrum at the magnetic zone center. As the generic characteristic of the conical state, a weak magnetic field (�2kOe) can modify the spin structure, leading to a remarkable change (terahertz magnetochromism) in spectral shape and intensity (by �200% ) of the electric-dipole-active magnetic resonance. The present observation implies that potentially many magnets with noncollinearly ordered spins may host such an electric-dipole-active resonance, irrespective of the presence or absence of Ps .
Kida, N.; Okuyama, D.; Ishiwata, S.; Taguchi, Y.; Shimano, R.; Iwasa, K.; Arima, T.; Tokura, Y.
Combined magnetic-dipole and electric-quadrupole hyperfine interactions in rare-earth orthoferrite ceramics
Perturbed-angular-correlation (PAC) spectroscopy was used to measure combined nuclear-magnetic-dipole and nuclear-electric-quadrupole interactions in rare-earth orthoferrite (REO) ceramics, RFeO3 (R=La,Pr,Nd,...,Lu). The rare-earth orthoferrites are canted antiferromagnets that have orthorhombically distorted perovskite structures. With the 111-->111Cd probe, the PAC measurements were made over a temperature range from laboratory temperature through the antiferromagnetic-to-paramagnetic transitions (740-620 K) and at or near 800 K. In the heavier REO's, the 111-->111Cd probe substitutes primarily into the rare-earth sites; and in the lighter REO's, it can substitute into both the Fe and the rare-earth sites. At the rare-earth sites, the probe undergoes a high-frequency electric-quadrupole interaction that is shifted in energy by a weak magnetic-dipole interaction. The direction of the associated magnetic hyperfine field is nearly perpendicular to the principal z axis of the electric-field-gradient (EFG) tensor. The magnitude of this field is small, and it may be produced by transferred spin density. In the heavier REO's, the rare-earth-site EFG's are nearly axially symmetric; and, as the rare-earth atomic number decreases, the EFG asymmetry increases. At the Fe sites, the probe undergoes a strong magnetic-dipole interaction that is shifted in energy by a low-frequency electric-quadrupole interaction, which involves very asymmetric EFG's. For PrFeO3, as an example, the strong magnetic-dipole interactions could be attributed to the presence of a supertransferred hyperfine field in which spin density is transferred via Fe-O-111Cd bonds. The predictions of a quantum-chemistry theory agree within a factor of 2 with the magnitude of this field. The direction of this field makes an angle of approximately 40� with the principal z axis of the EFG. For NdFeO3, similar results were obtained. The results of these experiments indicate that combined interactions can be measured in highly distorted crystals and that they can be analyzed. Moreover, these results indicate that PAC spectroscopy can provide new information about the magnitudes and directions of supertransferred hyperfine fields, which can be used as benchmarks for theoretical calculations.
Rearick, Todd M.; Catchen, Gary L.; Adams, James M.
Quantum dynamics of magnetic and electric dipoles and the geometric phase
We study the quantum dynamics of a neutral particle that posseses a permanent magnetic and electric dipole moments in the presence of an electromagnetic field. The analysis of this dynamics demonstrates the appearance of a quantum phase that combines the Aharonov-Casher effect and the He-Mckellar-Wilkens effect. We demonstrate that this phase is a special case of the geometric quantum phase. A series of field configurations where this phase would be found is presented. A generalized Casella-type effect is found in one of these configurations. A physical scenario for the quantum phase in an interferometric experiment is proposed.
Furtado, Claudio; Ribeiro, Carlos Alberto
Electric quadrupole and magnetic dipole transitions among 3d6 levels of Fe III
Radiative rates for electric quadrapole (E2) and magnetic dipole (M1) transitions among the lowest 32 levels belonging to the 3d6 configuration of doubly charged iron (Fe III) are calculated using our recently generated (Deb and Hibbert 2007 J. Phys. B: At. Mol. Opt. Phys. 40 F251) J-dependent configuration interaction (CI) wavefunctions. These results are then compared with other available theoretical calculations. It is found that there are large disagreements among various calculations for many of the transitions, with the present A-values for E2 and M1 transitions often significantly higher than the corresponding values in other calculations.
Deb, Narayan C.; Hibbert, Alan
The permanent electric dipole moments and magnetic g factors of uranium monoxide
Permanent electric dipole moments and magnetic g factors for uranium monoxide (UO) have been determined from analyses of optical Stark and Zeeman spectra recorded at a spectral resolution that approaches the natural linewidth limit. Numerous branch features in the previously characterized [L. A. Kaledin et al., J. Mol. Spectrosc. 164, 27 (1994)] (0,0) [18403]5-X(1)4 and (0,0) [18404]5-X(1)4 electronic transitions were recorded in the presence of tunable static electric (Stark effect) or magnetic (Zeeman effect) fields. The lines exhibited unusually large Zeeman tuning effects. A ligand field model and an ab initio electronic structure calculation [R. Tyagi, Ph.D. thesis, The Ohio State University (2005)] were used to interpret the ground state properties. The results indicate that the low energy electronic states of UO are sufficiently ionic for the meaningful application of ligand field theory models. The dipole moments and g factors were distinctly different for the three electronic states examined, which implies that these properties may be used to deduce the underlying electronic state configurations.
Heaven, Michael C.; Goncharov, Vasiliy; Steimle, Timothy C.; Ma, Tongmei; Linton, Colan
Magnetic dipole and electric quadrupole moments of the 229Th nucleus
We determine the magnetic dipole ? =0.360(7)?N and the electric quadrupole Q =3.11(6)eb moments of the 229Th nucleus by combining our high-precision calculations of the hyperfine constants with measurements reported in Campbell et al. [Phys. Rev. Lett. 106, 223001 (2011), 10.1103/PhysRevLett.106.223001]. We find that the previous value ? =0.46(4)?N [Gerstenkorn et al., J. Phys. (Paris) 35, 483 (1974), 10.1051/jphys:01974003506048300] is incorrect by 25%. We report a method for determining the accuracy of theoretical hyperfine constants B /Q and demonstrate that it can be used to extract the electric quadrupole moment Q with a 1%-2% uncertainty for a large number of nuclei. This approach allowed us to identify 40% inconsistencies in measurements of Ra+ hyperfine constants B.
Safronova, M. S.; Safronova, U. I.; Radnaev, A. G.; Campbell, C. J.; Kuzmich, A.
Analytical Formula of Induced Electric Fields in a Spherical Conductor by an Arbitral ELF Dipole Magnetic Field Source
Analytical formula of induced electric field at arbitral position in a spherical conductor by an arbitral ELF dipole magnetic field source is mathematically derived in vector form. Its validity is confirmed by comparing the analitical solutions with numerical solutions by the equivalent multipole moment method.
Mitsuhiro Kitano; Shoji Hamada; Tetsuo Kobayashi
Magnetic and electric dipole moments of the H {sup 3}{Delta}{sub 1} state in ThO
The metastable H {sup 3}{Delta}{sub 1} state in the thorium monoxide (ThO) molecule is highly sensitive to the presence of a CP-violating permanent electric dipole moment of the electron (eEDM) [E. R. Meyer and J. L. Bohn, Phys. Rev. A 78, 010502 (2008)]. The magnetic dipole moment {mu}{sub H} and the molecule-fixed electric dipole moment D{sub H} of this state are measured in preparation for a search for the eEDM. The small magnetic moment {mu}{sub H}=8.5(5)x10{sup -3} {mu}{sub B} displays the predicted cancellation of spin and orbital contributions in a {sup 3}{Delta}{sub 1} paramagnetic molecular state, providing a significant advantage for the suppression of magnetic field noise and related systematic effects in the eEDM search. In addition, the induced electric dipole moment is shown to be fully saturated in very modest electric fields (<10 V/cm). This feature is favorable for the suppression of many other potential systematic errors in the ThO eEDM search experiment.
Vutha, A. C.; Kirilov, E.; DeMille, D. [Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Spaun, B.; Gurevich, Y. V.; Hutzler, N. R.; Doyle, J. M.; Gabrielse, G. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)
The force on a magnetic dipole
The classical magnetic force on a magnetic dipole depends upon the model for the dipole. The usual electric current loop model for a magnetic dipole leads to the force F=?(m.B) on a magnetic dipole m in a magnetic field B. The separated magnetic charge model for a magnetic dipole leads to the force F=(m.?)B on a magnetic dipole. The latter expression is analogous to the force experienced by an electric dipole in an electric field. Here, some elementary examples are given where the force expressions yield entirely different forces on a magnetic dipole. Electromagnetism textbooks usually do not emphasize the difference between these force expressions; however, occasionally the difference is important for understanding experimental results. In the 1930s and 1940s the difference in force expressions was involved in a determination of the nature of the neutron dipole moment. At present, in the 1980s, the difference in the force expressions is central to a controversy over an experiment to test the proposed Aharonov-Casher effect.
Boyer, Timothy H.
Extended-aperture spatial diversity and polarizational diversity using a sparse array of electric dipoles or magnetic loops
A novel eigenstructure scheme of extended-aperture spatial diversity and polarizational diversity is proposed for 2D arrival angle estimation. This innovational method involves uniformly spaced triads (or pairs) of electric dipoles or magnetic loops, spaced much farther apart than a half-wavelength. An ESPRIT-based step produces arrival angle estimates that suffer cyclic ambiguity due to the extended spacing. Then, a closed-form integer
M. D. Zoltowski; K. T. Wong
Quantum electric dipole glass and frustrated magnetism near a critical point in Li2ZrCuO4
We report a new peculiar effect of the interaction between a sublattice of frustrated quantum spin-1/2 chains and a sublattice of pseudospin-1/2 centers (quantum electric dipoles) uniquely co-existing in the complex oxide ?-Li2ZrCuO4 (?Li2CuZrO4). 7Li nuclear magnetic resonance, Cu2+ electron spin resonance and a complex dielectric constant data reveal that the sublattice of Li+-derived electric dipoles orders glass like at Tgsime70 K yielding a spin site nonequivalency in the CuO2 chains. We suggest that such a remarkable interplay between electrical and spin degrees of freedom might strongly influence the properties of the spiral spin state in Li2ZrCuO4 that is close to a quantum ferromagnetic critical point. In particular that strong quantum fluctuations and/or the glassy behavior of electric dipoles might renormalize the exchange integrals affecting this way the pitch angle of the spiral as well as be responsible for the missing multiferroicity present in other helicoidal magnets.
Vavilova, E.; Moskvin, A. S.; Arango, Y. C.; Sotnikov, A.; Drechsler, S.-L.; Klingler, R.; Volkova, O.; Vasiliev, A.; Kataev, V.; B�chner, B.
Discrete symmetries on the light front and a general relation connecting the nucleon electric dipole and anomalous magnetic moments
We consider the electric dipole form factor, F3(q2), as well as the Dirac and Pauli form factors, F1(q2) and F2(q2), of the nucleon in the light-front formalism. We derive an exact formula for F3(q2) to complement those known for F1(q2) and F2(q2). We derive the light-front representation of the discrete symmetry transformations and show that time-reversal- and parity-odd effects are captured by phases in the light-front wave functions. We thus determine that the contributions to F2(q2) and F3(q2), Fock state by Fock state, are related, independent of the fundamental mechanism through which CP violation is generated. Our relation is not specific to the nucleon, but, rather, is true of spin-1/2 systems in general, be they lepton or baryon. The empirical values of the anomalous magnetic moments, in concert with empirical bounds on the associated electric dipole moments, can better constrain theories of CP violation. In particular, we find that the neutron and proton electric dipole moments echo the isospin structure of the anomalous magnetic moments, ?n�-?p.
Brodsky, Stanley J.; Gardner, Susan; Hwang, Dae Sung
We consider the electric dipole form factor, F{sub 3}(q{sup 2}), as well as the Dirac and Pauli form factors, F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}), of the nucleon in the light-front formalism. We derive an exact formula for F{sub 3}(q{sup 2}) to complement those known for F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}). We derive the light-front representation of the discrete symmetry transformations and show that time-reversal- and parity-odd effects are captured by phases in the light-front wave functions. We thus determine that the contributions to F{sub 2}(q{sup 2}) and F{sub 3}(q{sup 2}), Fock state by Fock state, are related, independent of the fundamental mechanism through which CP violation is generated. Our relation is not specific to the nucleon, but, rather, is true of spin-1/2 systems in general, be they lepton or baryon. The empirical values of the anomalous magnetic moments, in concert with empirical bounds on the associated electric dipole moments, can better constrain theories of CP violation. In particular, we find that the neutron and proton electric dipole moments echo the isospin structure of the anomalous magnetic moments, {kappa}{sup n}{approx}-{kappa}{sup p}.
Brodsky, Stanley J. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Gardner, Susan [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Hwang, Dae Sung [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of)
Discrete Symmetries on the Light Front and a General Relation connecting Nucleon Electric Dipole and Anomalous Magnetic Moments
We consider the electric dipole form factor, F{sub 3}(q{sup 2}), as well as the Dirac and Pauli form factors, F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}), of the nucleon in the light-front formalism. We derive an exact formula for F{sub 3}(q{sup 2}) to complement those known for F{sub 1}(q{sup 2}) and F{sub 2}(q{sup 2}). We derive the light-front representation of the discrete symmetry transformations and show that time-reversal- and parity-odd effects are captured by phases in the light-front wave functions. We thus determine that the contributions to F{sub 2}(q{sup 2}) and F{sub 3}(q{sup 2}), Fock-state by Fock-state, are related, independent of the fundamental mechanism through which CP violation is generated. Our relation is not specific to the nucleon, but, rather, is true of spin-1/2 systems in general, be they lepton or baryon. The empirical values of the anomalous magnetic moments, in concert with empirical bounds on the associated electric dipole moments, can better constrain theories of CP violation. In particular, we find that the neutron and proton electric dipole moments echo the isospin structure of the anomalous magnetic moments, {kappa}{sup n} {approx} -{kappa}{sup p}.
Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.; Hwang, Dae Sung; /Sejong U.
How to Introduce the Magnetic Dipole Moment
ERIC Educational Resources Information Center
We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the�
Bezerra, M.; Kort-Kamp, W. J. M.; Cougo-Pinto, M. V.; Farina, C.
Theoretical and computational multiple regression study of gastric electrical activity using dipole tracing from magnetic field measurements.
The biomagnetic inverse problem has captured the interest of both mathematicians and physicists due to its important applications in the medical field. As a result of our experience in analyzing the electrical activity of the gastric smooth muscle, we present here a theoretical model of the magnetic field in the stomach and a computational implementation whereby we demonstrate its realism and usefulness. The computational algorithm developed for this purpose consists of dividing the magnetic field signal input surface into centroid-based grids that allow recursive least-squares approximations to be applied, followed by comparison tests in which the locations of the best-fitting current dipoles are determined. In the second part of the article, we develop a multiple-regression analysis of experimental gastric magnetic data collected using Superconducting QUantum Interference Device (SQUID) magnetometers and successfully processed using our algorithm. As a result of our analysis, we conclude on statistical grounds that it is sufficient to model the electrical activity of the GI tract using only two electric current dipoles in order to account for the magnetic data recorded non-invasively with SQUID magnetometers above the human abdomen. PMID:23345871
Irimia, Andrei; Beauchamp, John J; Bradshaw, L Alan
Magnetic dipole transitions in the hydrogen molecule
In homonuclear molecules, such as H{sub 2}, the electric dipole transitions are strongly forbidden, and the transitions between rovibrational states are of the electric quadrupole type. We show, however, that magnetic dipole transitions also take place, although they are significantly weaker. We evaluate the probabilities of such transitions between several of the lowest rotational states and compare them with those of the corresponding electric quadrupole transitions.
Pachucki, Krzysztof [Institute of Theoretical Physics, University of Warsaw, Hoza 69, PL-00-681 Warsaw (Poland); Komasa, Jacek [Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, PL-60-780 Poznan (Poland)
Electric dipole radiation near a mirror
The emission of radiation by a linearly oscillating electric dipole is drastically altered when the dipole is close to the surface of a mirror. The energy is not emitted along optical rays, as for a free dipole, but as a set of four optical vortices. The field lines of energy flow spiral around a set of two lines through the dipole. At a larger distance from the dipole, singularities and isolated vortices appear. It is shown that these interference vortices are due to the vanishing of the magnetic field at their centers. In the plane of the mirror there is a singular circle with a diameter which is proportional to the distance between the dipole and the mirror. Inside this circle, all energy flows to a singularity on the mirror surface.
Li Xin; Arnoldus, Henk F. [Department of Physics and Astronomy, Mississippi State University, P. O. Drawer 5167, Mississippi State, Mississippi 39762-5167 (United States)
Wideband Shorted Bowtie Patch Antenna With Electric Dipole
A wideband directional antenna composed of a shorted bowtie patch antenna and an electric dipole is presented. Through this composition, an equivalent magnetic dipole due to the shorted bowtie patch antenna and an electric dipole are excited together. Almost equal radiation pattern in the E- and H-planes is obtained. The proposed antenna has a wide impedance bandwidth, which is over
Hang Wong; Ka-Ming Mak; Kwai-Man Luk
Relaxation rates of the monopole, magnetic dipole, and electric quadrupole moments of the 31P state of helium
The relaxation rates of the monopole, magnetic dipole, and electric quadrupole moments have been determined for the 31P state of helium excited by electron impact, The data are determined from atomic lifetimes using linear and circular polarization analyzed radiation with the electron-photon delayed coincidence technique. This has permitted the direct observation of the time dependence of all the off-diagonal elements of the density matrix of the excited state. The implications for atomic state information determined from polarization and angular correlation methods are indicated.
Williams, J. F.; Mikosza, A. G.; Wang, J. B.; Wedding, A. B.
Nb3Sn dipole magnets
Multifilamentary Nb3Sn conductors suitable for use in accelerator magnets have been under development at BNL for a number of years. To date three one meter long dipole magnets have been constructed from braided conductor which had been reacted prior to winding. The first of these dipoles and the method of construction has been described in an earlier paper. The most
W. Sampson; S. Kiss; K. Robins; A. McInturff
CrRb: A molecule with large magnetic and electric dipole moments
We report calculations of Born-Oppenheimer potential energy curves of the chromium-rubidium heteronuclear molecule ({sup 52}Cr{sup 87}Rb), and the long-range dispersion coefficient for the interaction between ground state Cr and Rb atoms. Our calculated van der Waals coefficient (C{sub 6}=1770 a.u.) has an expected error of 3%. The ground state {sup 6{Sigma}+} molecule at its equilibrium separation has a permanent electric dipole moment of d{sub e}(R{sub e}=3.34Angstrom)=2.90 D. We investigate the hyperfine and dipolar collisions between trapped Cr and Rb atoms, finding elastic to inelastic cross section ratio of 10{sup 2}-10{sup 3}.
Pavlovic, Z. [ITAMP, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States); Department of Physics, University of Connecticut, Storrs, Connecticut 06269-3046 (United States); Sadeghpour, H. R. [ITAMP, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States); Cote, R. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269-3046 (United States); Roos, B. O. [Department of Theoretical Chemistry, University of Lund, S-221 00 Lund (Sweden)
Dipole Moments of Weak, Electrically Small Emitters from TEM-Cell Measurements.
The report presents a new method for determining the equivalent electric and magnetic dipole moments of an electrically small emitter from TEM-cell measurements. The electric dipole moments are determined from open-circuit measurements, and the magnetic d...
D. A. Hill K. H. Cavcey
Electric Dipole Moments of Dyon and `Electron'
The electric and magnetic dipole moments of dyon fermions are calculated within N = 2 supersymmetric Yang-Mills theory including the ?-term. It is found, in particular, that the gyroelectric ratio deviates from the canonical value of 2 for the monopole fermion (n_{m} = 1, n_{e} = 0) in the case ? ? 0. Then, applying the S-duality transformation to the result for the dyon fermions, we obtain an explicit prediction for the electric dipole moment (EDM) of the charged fermion (`electron'). It is thus seen that the approach presented here provides a novel method for computing the EDM induced by the ?-term.
Kobayashi, M.; Kugo, T.; Tokunaga, T.
Progress in metamaterials: Magnetic hybridization of electric dipole resonance and inhomogeneous structures for thin-film lenses
From earlier theoretical work and practical implementation, understanding of negative index metamaterials (NIMs) has advanced rapidly. Much effort has been put into extending NIMs in the near-infrared (NIR) and in visible regions, where simple scaling of the magnetic response of the structures used for RF breaks down at the NIR. As a solution, a new structure in the form of a fishnet has emerged, and has been shown to successfully act as a new metamaterial in the infrared and visible regions. Attention in the research community is now turning to the direct applications. Here we report progress in the field of metamaterials for the magnetic hybridization of the electric dipole resonance and inhomogeneous metamaterial structures. From the fundamental and, possibly, application points of view, it is of interest to consider the coupling between the metamaterial magnetic resonance and electric dipole resonances of the absorbing species located in the metamaterial unit cell. Simple resonance coupling model and numerical rigorous coupled wave analysis (RCWA) were used to investigate the effect of adding a dielectric with a dipole absorption peak to a fishnet metamaterial. Anti-crossing behavior and an exchange of oscillator strength as the metamaterial structural resonance is tuned through the absorption resonance were obtained. Response of the NIM structure with a dielectric material without an absorber shows only a single resonant peak, resulting from the coupling of the broadband negative epsilon with the structurally resonant negative micro associated with the LC circuit between the two metal plates. With the addition of a dipole absorber in the dielectric, the NIM exhibits doubly resonant behavior. Presence of an electric dipole resonance in the dielectric of the fishnet structure manifests itself in a modification of the magnetic permeability, which in turn modifies the negative index behavior. A set of experimental samples were fabricated using standard lithographic processing. An Al-BCB-Al fishnet structure was used. Transmission data was obtained by FTIR. Plotting positions of the resonance peaks in the transmission response against o0 clearly shows coupling between the resonances with hybridization behavior First step in development of possible application for the metamaterials was done by Driscoll in 2006. He demonstrated a free space focusing by means of Split Ring Resonator structure. We take the next step and demonstrate that fishnet inhomogeneous metamaterial structures can be used for the thin-film lenses in the NIR regime. Here we report the first numerical demonstration of a flat, thin-film (<250 nm) GRIN positive lens operating in the NIR (�1.55 microm) and based on the fishnet structure. This represents a significant advance toward applications as well as steps forward in design complexity and construction technique. Complex RCWA based, parametric studies and the optimization for the largest achievable phase shift with smallest variation in transmission have been performed. Proposed (64x64)lambda2 area experimental samples will have small edge effects and act as f/26 lens. The F number can be significantly improved by stacking several layers of NIMs. Preliminary experimental results show a successful pattern transferring in the photoresist layer by the use of Imaging Interferometric Lithography (IIL) tool.
Smolev, Svyatoslav
The permanent electric dipole moments and magnetic hyperfine interaction in the A 2? state of yttrium monosulfide
The optical Stark effect in the (0,0) A 2?-X 2?+ band systems of a yttrium monosulfide, YS, supersonic molecular beam sample have been analyzed to produce the magnitude of the permanent electric dipole moments, | ?|, for the A 2?3/2, and A 2?1/2 states of 5.9(2), and 6.8(1) D, respectively. Small splittings in the field free A 2?3/2-X 2?+ and A 2?1/2-X 2?+ spectra were analyzed to produce the magnetic hyperfine spectroscopic parameters a=-36(6), c=111(7), and d=-107(6) MHz for the A 2? state. Transition frequencies of the low rotational lines in the (0,0) A 2?r-X 2?+ band system were measured and analyzed to produce the first complete set of fine structure parameters for the A 2?r state. A comparison with YO and other isovalent molecules is made.
Steimle, T. C.; Virgo, Wilton
Multiferroicity in an organic charge-transfer salt that is suggestive of electric-dipole-driven magnetism
Multiferroics, showing simultaneous ordering of electrical and magnetic degrees of freedom, are remarkable materials as seen from both the academic and technological points of view. A prominent mechanism of multiferroicity is the spin-driven ferroelectricity, often found in frustrated antiferromagnets with helical spin order. There, as for conventional ferroelectrics, the electrical dipoles arise from an off-centre displacement of ions. However, recently a different mechanism, namely purely electronic ferroelectricity, where charge order breaks inversion symmetry, has attracted considerable interest. Here we provide evidence for ferroelectricity, accompanied by antiferromagnetic spin order, in a two-dimensional organic charge-transfer salt, thus representing a new class of multiferroics. We propose a charge-order-driven mechanism leading to electronic ferroelectricity in this material. Quite unexpectedly for electronic ferroelectrics, dipolar and spin order arise nearly simultaneously. This can be ascribed to the loss of spin frustration induced by the ferroelectric ordering. Hence, here the spin order is driven by the ferroelectricity, in marked contrast to the spin-driven ferroelectricity in helical magnets.
Lunkenheimer, P.; Muller, J.; Krohns, S.; Schrettle, F.; Loidl, A.; Hartmann, B.; Rommel, R.; de Souza, M.; Hotta, C.; Schlueter, J. A.; Lang, M. (Materials Science Division); (Univ. Augsburg); (Goethe-Univ. Frankfurt); (Kyoto Sangyo Univ.)
Lunkenheimer, Peter; M�ller, Jens; Krohns, Stephan; Schrettle, Florian; Loidl, Alois; Hartmann, Benedikt; Rommel, Robert; de Souza, Mariano; Hotta, Chisa; Schlueter, John A.; Lang, Michael
Locating a Buried Magnetic Dipole
Five measurements of the magnetic-field vector near the surface of the earth are shown to be sufficient to determine the orientation and location of a buried magnetic dipole. A discussion of field experiments which demonstrate the location concept is included.
Thurlow W. H. Caffey; Louis Romero
Magnetic monopoles and dipoles in quantum mechanics
The force on and the energy of a ''di-monopole'', which is the limiting case of a dipole made from two monopoles at zero separation and finite magnetic moment, interacting with an externally fixed magnetic field resulting from an electric current, is considered. A model involving only a monopole is used to illustrate the physical principles involved when magnetic sources move in a solenoidal field whose source is an electric current. The problems encountered in Hamiltonian theory are discussed. 5 refs., 3 figs. (LEW)
Lipkin, H.J.; Peshkin, M.
Conductor development for high field dipole magnets
Historically, improvements in dipole magnet performance have been paced by improvements in the superconductor available for use in these magnets. The critical conductor performance parameters for dipole magnets include current density, piece length, effective filament size, and cost. Each of these parameters is important for efficient, cost effective dipoles, with critical current density being perhaps the most important. Several promising
R. M. Scanlan; D. R. Dietderich; H. C. Higley
Magnetic Dipole Fields in Unsaturated Cubic Crystals
The mean value of the randomly directed local magnetic field at a lattice point in each of two cubic arrays, (I) and (F), of equal magnetic dipoles is computed under the following restrictions: (a) The orientation of neighboring dipoles is independent. (b) The direction of each dipole axis is one of the easy directions of magnetization for a ferromagnetic metal
L. W. McKeehan
Magnetic-dipole photo-recombination in ultracold hydrogen plasma
The cross section for magnetic-dipole photodisintegration of the negative hydrogen ion has been calculated within the zero-range-potential approximation. The magnetic-dipole cross section for photodetachment within the very narrow range of energy near the process threshold is predicted to dominate over the electric-dipole one. It is shown that in ultracold hydrogen plasma at temperatures below T = 3.29 � 10?4 K the magnetic-dipole photo-recombination becomes an important mechanism of electron capture by hydrogen atoms.
Baltenkov, A. S.
Measuring the Forces between Magnetic Dipoles
We describe a simple undergraduate lab in which students determine how the force between two magnetic dipoles depends on their separation. We consider the case where both dipoles are permanent and the case where one of the dipoles is induced by the field of the other (permanent) dipole. Agreement with theoretically expected results is quite good.
Gayetsky, Lisa E.; Caylor, Craig L.
Magnetic Dipole Fields in Unstrained Cubic Crystals
Magnetic field components in certain cubic arrays of equal parallel dipoles are computed by two methods for points on the boundary of a dipole domain and for points near a vacated dipole position. The results may be of use in theories of ferromagnetism. Characteristic constants for a nonpolar cubic array of dipoles, previously computed by Bouman, are recomputed more precisely.
The Levitated Dipole Experiment (LDX) magnet system
In the Levitated Dipole Experiment (LDX), a hot plasma is formed about a levitating superconducting dipole magnet in the center of a 5 m diameter vacuum vessel. The levitated magnet is suspended magnetically during an eight hour experimental run, then lowered and recooled overnight. The floating F-coil magnet consists of a layer-wound magnet with 4 sections, designed to wrap flux
J. H. Schultz; J. Kesner; J. V. Minervini; A. Radovinsky; S. Pourrahimi; B. Smith; P. Thomas; P. W. Wang; A. Zhukovsky; R. L. Myatt; S. Kochan; M. Mauel; D. Garnier
Magnetic Field of a Dipole and the Dipole-Dipole Interaction
With a data-acquisition system and sensors commercially available, it is easy to determine magnetic fields produced by permanent magnets and to study the dipole-dipole interaction for different separations and angular positions of the magnets. For sufficiently large distances, the results confirm the 1/R[superscript 3] law for the magnetic field�
Kraftmakher, Yaakov
Pulsar Pair Cascades in a Distorted Magnetic Dipole Field
We investigate the effect of a distorted neutron star dipole magnetic field on pulsar pair cascade multiplicity and pair death lines. Using a simple model for a distorted dipole field that produces an offset polar cap (PC), we derive the accelerating electric field above the PC in space-charge-limited flow. We find that even a modest azimuthally asymmetric distortion can significantly
Alice K. Harding; Alex G. Muslimov
New ? level mixing and nuclear magnetic resonance method for measuring magnetic dipole and electric quadrupole moments of short-lived nuclei
The level-mixing resonance technique applied to ?-decaying nuclei (?-LMR) is a well-established tool for measuring the ground state quadrupole moments of nuclei away from stability. These experiments yield the quadrupole to magnetic moment ratio, provided the electric field gradient (EFG) of the implanted nuclei in the crystal is known. By combining ?-LMR with ? nuclear magnetic resonance (?-NMR), both the quadrupole moment Q and the magnetic moment ? can be simultaneously extracted in a single experiment. A major advantage of this technique is that the initial nuclei need only to be aligned, and not necessarily polarized. Alignment is generally easier to produce than polarization, and occurs at the highest yield point in the nuclear reaction mechanism. This is an especially important consideration in the study of dipole and quadrupole moments of nuclei in the region of the drip lines. We report here the successful application of this combined technique to the known case of 12B(Mg). The main features of the LMR-NMR technique are described.
Coulier, N.; Neyens, G.; Teughels, S.; Balabanski, D. L.; Coussement, R.; Georgiev, G.; Ternier, S.; Vyvey, K.; Rogers, W. F.
Dipole Relaxation in an Electric Field.
Derives an expression for the orientational entropy of a rigid rod (electric dipole) from Boltzmann's equation. Subsequent application of Newton's second law of motion produces Debye's classical expression for the relaxation of an electric dipole in a viscous medium. (Author/GS)
Neumann, Richard M.
Magnetic dipole discharges. III. Instabilities
Instabilities in a cross-field discharge around a permanent magnet have been investigated. The permanent magnet serves as a cold cathode and the chamber wall as an anode. The magnet is biased strongly negative and emits secondary electrons due to impact of energetic ions. The electrons outside the sheath are confined by the strong dipolar magnetic field and by the ion-rich sheath surrounding the magnet. The electron energy peaks in the equatorial plane where most ionization occurs and the ions are trapped in a negative potential well. The discharge mechanism is the same as that of cylindrical and planar magnetrons, but here extended to a 3-D cathode geometry using a single dipole magnet. While the basic properties of the discharge are presented in a companion paper, the present focus is on various observed instabilities. The first is an ion sheath instability which oscillates the plasma potential outside the sheath below the ion plasma frequency. It arises in ion-rich sheaths with low electron supply, which is the case for low secondary emission yields. Sheath oscillations modulate the discharge current creating oscillating magnetic fields. The second instability is current-driven ion sound turbulence due to counter-streaming electrons and ions. The fluctuations have a broad spectrum and short correlation lengths in all directions. The third type of fluctuations is spiky potential and current oscillations in high density discharges. These appear to be due to unstable emission properties of the magnetron cathode.
Stenzel, R. L.; Urrutia, J. M. [Department of Physics and Astronomy, University of California Los Angeles, California 90095-1547 (United States)] [Department of Physics and Astronomy, University of California Los Angeles, California 90095-1547 (United States); Ionita, C.; Schrittwieser, R. [Institute for Ion Physics and Applied Physics, University of Innsbruck A-6020 Innsbruck (Austria)] [Institute for Ion Physics and Applied Physics, University of Innsbruck A-6020 Innsbruck (Austria)
Spin dephasing in a magnetic dipole field.
Transverse relaxation by dephasing in an inhomogeneous field is a general mechanism in physics, for example, in semiconductor physics, muon spectroscopy, or nuclear magnetic resonance. In magnetic resonance imaging the transverse relaxation provides information on the properties of several biological tissues. Since the dipole field is the most important part of the multipole expansion of the local inhomogeneous field, dephasing in a dipole field is highly important in relaxation theory. However, there have been no analytical solutions which describe the dephasing in a magnetic dipole field. In this work we give a complete analytical solution for the dephasing in a magnetic dipole field which is valid over the whole dynamic range. PMID:23004789
Ziener, C H; Kampf, T; Reents, G; Schlemmer, H-P; Bauer, W R
Dynamics of an electric dipole moment in a stochastic electric field.
The mean-field dynamics of an electric dipole moment in a deterministic and a fluctuating electric field is solved to obtain the average over fluctuations of the dipole moment and the angular momentum as a function of time for a Gaussian white-noise stochastic electric field. The components of the average electric dipole moment and the average angular momentum along the deterministic electric-field direction do not decay to zero, despite fluctuations in all three components of the electric field. This is in contrast to the decay of the average over fluctuations of a magnetic moment in a stochastic magnetic field with Gaussian white noise in all three components. The components of the average electric dipole moment and the average angular momentum perpendicular to the deterministic electric-field direction oscillate with time but decay to zero, and their variance grows with time. PMID:24032795
Band, Y B
SSC collider dipole magnet end mechanical design
The authors describe the mechanical design of the ends of Superconducting Super Collider (SSC) dipole magnets to be constructed and tested at Fermilab. Coil end clamps, end yoke configuration, and end plate design are discussed. Loading of the end plate by axial Lorentz forces is examined. Relevant data from 40 mm and 50 mm aperture model dipole magnets built and
S. W. Delchamps; R. C. Bossert; J. Carson; K. Ewald; H. Fulton; J. Kerby; W. Koska; J. Strait; M. Wake; K. K. Leung
Sns ring dipole magnetic field quality.
The large acceptance and compact size of the Spallation Neutron Source (SNS) ring implies the use of short, large aperture dipole magnets, with significant end field errors. The SNS will contain 32 such dipoles. We report magnetic field measurements of th...
Wanderer Jackson Jain Y. Lee Meng Papaphilippou Spataro Tepikian Tsoupas Wei
Electrically Small Switchable Chaotic Dipole Antenna.
An electrically small dipole antenna loaded with Chua's oscillator as a nonlinear load is analyzed. By using certain values for the linear reactive and resistive elements of this circuit, various types of periodic, period- doubled, and chaotic behavior th...
P. L. Overfelt D. J. White
Accelerator Magnets:. Dipole, Quadrupole and Sextupole
The main characteristics of the magnet design and performance of lattice magnets including dipole, quadrupole, and sextupole magnets, will be presented. The design and construction constraints of the conventional, steel iron yoke, and the direct-current magnets are also discussed. The equations of the ideal pole shapes of the dipole, quadrupole, and sextupole, are used to design the magnets. Several two- or three-dimensional calculation codes are introduced to simulate the magnets. Moreover, a brief description of the injection magnets is also presented. Finally, field measurement and mapping methods are introduced and the results from field measurements by means of a Hall probe are discussed.
Hwang, C. S.
We investigate the effect of a distorted neutron star dipole magnetic field\\u000aon pulsar pair cascade multiplicity and pair death lines. Using a simple model\\u000afor a distorted dipole field that produces an offset polar cap, we derive the\\u000aaccelerating electric field above the polar cap in space charge limited flow.\\u000aWe find that even a modest azimuthally asymmetric distortion
Nonlinearity of Nuclotron Superconducting Dipole Magnetic Field.
The nonlinearity of magnetic field for superconducting dipole of nuclotron has been investigated for all current operating range. It is shown that the nonlinearity is 0.1% in the dipole central region at RN=1.9 cm distance of normalized radius. The integr...
Z. V. Borisovskaya A. M. Donyagin A. A. Smirnov I. A. Shelaev
Capture of a Dirac monopole by a magnetic dipole
The relativistic Hamiltonian between a monopole and a magnetic dipole is derived from field theory with a singular action along a string. In addition to the expected potential of the form g?-->.r-->r3, there is a relativistic velocity-dependent, vector potential A~ without which the Hamiltonian would not be essentially self-adjoint. Combining with earlier results we have now the most general relativistic stationary Hamiltonian between two particles (dyons) (e1, g1, a1) and (e2, g2, a2) both with electric and magnetic charges and (anomalous) magnetic dipole moments.
Barut, A. O.; Xu, Bo-Wei
The field of a screened magnetic dipole
NASA Technical Reports Server (NTRS)
The purpose of this note is to quantitatively study the asymptotic behavior of the dipole magnetic field in the tail region of a paraboloidal or cylindrical model of the magnetosphere, assuming the complete screening of the internal field by magnetopause currents. This screening assumption is equivalent to imposing the boundary condition that the normal component of the magnetic field is zero at the magnetopause. With this boundary condition, the screened dipole field falls off exponentially with distance down the tail, in sharp constrast to the bare dipole field. Analytic expressions for a cylindrical and paraboloidal magnetopause are given.
Greene, J. M.; Miller, R. L.
Coldmass for lhc dipole insertion magnets..
Brookhaven National Laboratory (BNL) is building a number of magnets for the insertion regions of the Large Hadron Collider (LHC). This paper presents the magnetic design and the expected field quality in 2-in-1 dipole magnets. A unique feature of this co...
A. Gupta Alforque Anerella Kelly Plate Rufer
It is important to identify the locations of electromagnetic (EM) noise sources within the electrical and electronic equipment, for the reduction of undesired noise emissions from it. In this study, by applying the MUSIC algorithm, we localize low-frequency (less than MHz) magnetic dipole sources (small current loops), which have incoherent or coherent time-series of waveforms. The numerical simulations and the
S Yagitani; M. Kawauchi; I. Nagano; E. Okumura; Y. Yoshimura
Accretion to stars with non-dipole magnetic fields
Disc accretion to a rotating star with a non-dipole magnetic field is investigated for the first time in full three-dimensional magnetohydrodynamic simulations. We investigated the cases of (1) pure dipole, (2) pure quadrupole, and (3) dipole plus quadrupole fields. The quadrupole magnetic moment D is taken to be parallel to the dipole magnetic moment mu, and both are inclined relative
M. Long; M. M. Romanova; R. V. E. Lovelace
Quantum holonomies for an electric dipole moment
In this Letter, we obtain the quantum holonomies for a neutral particle with a permanent electric dipole moment based on the analogue effects of the He-McKellar-Wilkens effect and the Scalar Aharonov-Bohm effect and show a new proposal for implementing one-qubit quantum gates.
Bakke, Knut; Furtado, Claudio
Coldmass for LHC Dipole Insertion Magnets
Brookhaven National Laboratory (BNL) is building a number of magnets for the insertion regions of the Large Hadron Collider (LHC). This paper presents the magnetic design and the expected field quality in 2-in-1 dipole magnets. A unique feature of this cold mass design is the use of an oblate-shaped yoke. This concept permits a variety of BNL-built magnets to have
R. Gupta; R. Alforque; M. Anerella; E. Kelly; S. Plate; C. Rufer; P. Wanderer; E. Willen; K. C. Wu
Coldmass for LHC Dipole Inserti on Magnets
Abstract, Brookhaven National Laboratory (BNL) is build-ing a number of magnets for the insertion regions of the Large Hadron Collider (LHC). This paper presents the magnetic de-sign and the expected field quality in 2-in-1 dipole magnets. A unique feature of this coldmass design is the use of an oblate-shaped yoke. This concept permits a variety of BNL-built mag-nets to have
Interaction of a plasma flow with a magnetic dipole field
The interaction of a streaming plasma with a magnetic dipole field is studied in the framework of a linearized, two-fluid continuum description. For the case of low-density flows, in which the pressure gradients are small in comparison to magnetic and electric forces, it is possible to extend the solution beyond the first-order one, which gives the distribution of induced current
Ronald C. Oberth
Effect of spin excitations with simultaneous magnetic- and electric-dipole character on the static magnetoelectric properties of multiferroic materials
We derive a sum rule to demonstrate that the static magnetoelectric (ME) effect is governed by optical transitions that are simultaneously excited by the electric and magnetic components of light. The ME sum rule is applicable to a broad class of materials lacking the spatial inversion and the time-reversal symmetries, including multiferroic compounds. Due to the dynamical ME effect, the optical excitations in these materials can exhibit directional dichroism, i.e., the absorption coefficient can be different for counter-propagating light beams. According to the ME sum rule, the magnitude of the linear ME effect of a material is mainly determined by the directional dichroism of its low-energy optical excitations. An application of the sum rule to the multiferroic Ba2CoGe2O7, Sr2CoSi2O7, and Ca2CoSi2O7 shows that in these compounds the static ME effect is mostly governed by the directional dichroism of the spin-wave excitations in the giga-terahertz spectral range. On this basis, we argue that the studies of directional dichroism and the application of the ME sum rule promote the synthesis of new materials with large static ME effect.
Szaller, D�vid; Bord�cs, S�ndor; Kocsis, Vilmos; R��m, Toomas; Nagel, Urmas; K�zsm�rki, Istv�n
Zeeman frequency shifts in an optical dipole trap used to search for an electric-dipole moment
We calculate the Zeeman frequency shifts due to interactions with the light in a far-off-resonance optical dipole trap. These shifts are important for potential use of such a trap to search for an atomic permanent electric-dipole moment (EDM). We present numerical results for Cs and Hg, as examples of paramagnetic and diamagnetic atoms. The vector and tensor light shifts are calculated for a large range of trap optical frequencies, for both red-detuned and blue-detuned traps. We also consider frequency shifts resulting from magnetic dipole and electric quadrupole transitions mixed in by a static electric field. These shifts are particularly important for EDM experiments since they are linear in the electric field. The Zeeman frequency shifts represent a substantial problem for EDM experiments in a dipole trap and must be controlled with care to achieve theoretical sensitivity.
Romalis, M. V.; Fortson, E. N.
New limit on the electron electric dipole moment
We present the result of our most recent search for T-violation in 205Tl, which is interpreted in terms of an electric dipole moment of the electron de. We find de = (6.9 plus/minus 7.4) times 10{sup -28} e cm. The present apparatus is a major upgrade of the atomic beam magnetic resonance device used to set the previous limit on de.
Regan, B.C.; Commins, Eugene D.; Schmidt, Christian J.; DeMille, David
Molecules with an induced dipole moment in a stochastic electric field.
The mean-field dynamics of a molecule with an induced dipole moment (e.g., a homonuclear diatomic molecule) in a deterministic and a stochastic (fluctuating) electric field is solved to obtain the decoherence properties of the system. The average (over fluctuations) electric dipole moment and average angular momentum as a function of time for a Gaussian white noise electric field are determined via perturbative and nonperturbative solutions in the fluctuating field. In the perturbative solution, the components of the average electric dipole moment and the average angular momentum along the deterministic electric field direction do not decay to zero, despite fluctuations in all three components of the electric field. This is in contrast to the decay of the average over fluctuations of a magnetic moment in a Gaussian white noise magnetic field. In the nonperturbative solution, the component of the average electric dipole moment and the average angular momentum in the deterministic electric field direction also decay to zero. PMID:24229157
Band, Y B; Ben-Shimol, Y
Recent developments in neutron electric dipole moment and related CP violating quantities
We summarize recent theoretical developments in CP violation related to the neutron electric dipole moment, chromo-electric dipole moments for quarks, chromo-electric dipole moment for gluon, and electric dipole moments for electron and W boson. 31 refs.
Chang, D. (Northwestern Univ., Evanston, IL (USA). Dept. of Physics and Astronomy Fermi National Accelerator Lab., Batavia, IL (USA))
Phase transitions in lattices of magnetic dipoles
Hexagonal magnetic-dipole lattices containing three to six rows are investigated. Conditions of the excitation of phase transitions that change the orientation configuration of the system are revealed on the basis of a numerical analysis. The changes in the magnetic moment of the system and in the energy of dipole-dipole interaction upon the emergence of phase transitions are found. Both symmetric phase transitions propagating identically on the two sides of the lattice away from the excitation region and asymmetric phase transitions such in which the configurations of the system to the left and to the right of the excitation region are different are considered. Conditions under which there occur unidirectional phase transitions in which either the left-or the right-hand front of the phase transition propagates along the lattice are found.
Shutyi, A. M.
Electric dipole moment of light nuclei
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
Afnan, Iraj R. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001 (Australia); Gibson, Benjamin F. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
The slowing down of a homogeneous supersonic plasma flow in an axial magnetic dipole field at the occurrence of a steady shock wave, taking into account a flow without electric currents and magnetic fields
An experimental investigation is conducted of the effect of an intense magnetic dipole field on a homogeneous supersonic argon plasma flow. The dipole field is aligned symmetrically to the jet axis and the free jet has a Mach number of about 4. The studies show an occurrence of large circular currents which reduce the effect of the magnetic field on
R. Ullrich
AC loss measurement of SSC dipole magnets.
AC losses in full length and 1.5 m model SSC collider dipoles were successfully measured by the direct observation of energy flow into and out of magnets during a ramp cycle. The measurement was performed by using two double-integrating type digital volt ...
S. Delchamps R. Hanft T. Jaffery W. Kinney W. Koska
The Case of the Disappearing Magnetic Dipole
The problem of an oscillating magnetic dipole at the centre of a lossless dielectric spherical shell is considered. For simplicity, the free-space wavelength is taken to be much greater than the shell radii, but the relative permittivity [epsilon][subscript r] of the shell is taken as much greater than unity, so the wavelength in the shell could�
Gough, W.
Magnetic Dipole Moment of RV Alliance.
A SACLANTCEN magnetometry sea trial was performed in September 1998 in the northern Tyrrhenian Sea in the vicinity of the Formiche di Grosseto islands. One of the trial objectives concerned the measurement of the magnetic dipole moment of the NATO researc...
J. Watermann
Magnetic Dipole Fields in Dislocated Cubic Crystals
A search is made for magnetic stability of orientation in cubic arrays of parallel dipoles subjected to dislocations of two sorts. In the first sort of dislocation cubic symmetry is lost but the dislocation is homogeneous. In the second sort, which simulates incipient or residual slip between two parts of one crystal, cubic symmetry is retained by each part separately,
Progress towards an electron electric dipole moment measurement with laser-cooled atoms
This dissertation recounts the progress made towards a measurement of the electron electric dipole moment. The existence of a permanent electric dipole moment of any fundamental particle would imply that both time reversal and parity invariance are violated. If an electric dipole moment were measured within current experimental limits it would be the first direct evidence for physics beyond the standard model. For our measurement we use laser-cooled alkali atoms trapped in a pair of 1D optical lattices. The lattices run through three electric field plates so that the two groups of atoms see opposing electric fields. The measurement chamber is surrounded by a four layer mu-metal magnetic shield. Under electric field quantization, the atoms are prepared in a superposition of magnetic sublevels that is sensitive to the electron electric dipole moment in Ramsey-like spectroscopy. The experiment requires very large electric fields and very small magnetic fields. Engineering a system compatible with both of these goals simultaneously is not trivial. Searches for electric dipole moments using neutral atoms in optical lattices have much longer possible interaction times and potentially give more precise information about the inherent symmetry breaking than other methods. This comes at the cost of a higher sensitivity to magnetic fields and possible sources of error associated with the trapping light. If noise and systematic errors can be controlled to our design specifications our experiment will significantly improve the current experimental limit of the electron electric dipole moment.
Solmeyer, Neal
Absorption intensities of rovibronic transitions in the A-band of 16O2: Analysis and calculation of magnetic dipole and electric quadrupole contributions
The recently measured magnetic dipole (M1) absorption intensities of rovibronic transitions in the A-band (b?g+1-X?g-3, 030 band) of 16O2 are theoretically analyzed employing a model in which the b?g+1:X?g-3 mutual perturbations are treated to a sufficient degree of accuracy. Effects of rotational perturbations became manifest in the data analysis and rovibronic correction parameters are needed to reconcile theory and experiment. At a subtle level there is evidence of Herman-Wallis (HW) type effect arising from vibration-rotation interaction in the b and X states. The functional form for the HW correction factor is arrived at from first principles. The final calculations reproduce the measured intensities to fraction of a percent, well within the measurement accuracy. The present analysis leads to the value <=0.02679(4) ?B for the M1 transition moment, and the spontaneous emission rate (Einstein-A coefficient) ?0,0=0.0874 s-1. For the sake of completeness, the electric quadrupole (E2) contribution to the observed intensities is also quantitatively assessed.
Balasubramanian, T. K.; Mishra, Adya P.; Kshirsagar, R. J.
Electric Dipole Theory of Chemical Synaptic Transmission
PubMed Central
In this paper we propose that chemicals such as acetylcholine are electric dipoles which when oriented and arranged in a large array could produce an electric field strong enough to drive positive ions over the junction barrier of the post-synaptic membrane and thus initiate excitation or produce depolarization. This theory is able to explain a great number of facts such as cleft size, synaptic delay, nonregeneration, subthreshold integration, facilitation with repetition, and the calcium and magnesium effects. It also shows why and how acetylcholine could act as excitatory or inhibitory transmitters under different circumstances. Our conclusion is that the nature of synaptic transmission is essentially electrical, be it mediated by electrical or chemical transmitters.
Wei, Ling Y.
Permanent electric dipole moment of molybdenum carbide
High resolution optical spectroscopy has been used to study a molecular beam of molybdenum monocarbide (MoC). The Stark effect of the Re(0) and Qfe(1) branch features of the [18.6] 3?1-X 3?-(0,0) band system of 98MoC were analyzed to determine the permanent electric dipole moments ?e of 2.68(2) and 6.07(18) D for the [18.6] 3?1(?=0) and X 3?-(?=0) states, respectively. The dipole moments are compared with the experimental value for ruthenium monocarbide [T. C. Steimle et al., J. Chem. Phys. 118, 2620 (2003)] and with theoretical predictions. A molecular orbital correlation diagram is used to interpret the observed and predicted trends of ground state ?e values for the 4d-metal monocarbides series.
Wang, Hailing; Virgo, Wilton L.; Chen, Jinhai; Steimle, Timothy C.
Permanent electric dipole moment of molybdenum carbide.
High resolution optical spectroscopy has been used to study a molecular beam of molybdenum monocarbide (MoC). The Stark effect of the R(e)(0) and Q(fe)(1) branch features of the [18.6] (3)Pi(1)-X (3)Sigma(-)(0,0) band system of (98)MoC were analyzed to determine the permanent electric dipole moments mu(e) of 2.68(2) and 6.07(18) D for the [18.6] (3)Pi(1)(nu=0) and X (3)Sigma(-)(nu=0) states, respectively. The dipole moments are compared with the experimental value for ruthenium monocarbide [T. C. Steimle et al., J. Chem. Phys. 118, 2620 (2003)] and with theoretical predictions. A molecular orbital correlation diagram is used to interpret the observed and predicted trends of ground state mu(e) values for the 4d-metal monocarbides series. PMID:17902898
Wang, Hailing; Virgo, Wilton L; Chen, Jinhai; Steimle, Timothy C
New experimental limit on the electron electric dipole moment
A search for the electron electric dipole moment {ital d}{sub {ital e}} is carried out with two counterpropagating beams of ground-state {sup 205}Tl. The experiment employs atomic-beam magnetic resonance with separated oscillatory fields combined with laser state selection and fluorescence detection. Extensive tests were made for possible systematic effects. The result for the atomic electric dipole moment is {ital d}{sub {ital a}}=(1.6 {plus minus}5.0){times}10{sup {minus}24} {ital e} cm, where the uncertainty includes equal statistical and systematic contributions. This yields {ital d}{sub {ital e}}=({minus}2.7{plus minus}8.3) {times}10{sup {minus}27} {ital e} cm, assuming the ratio {ital d}{sub {ital a}}/{ital d}{sub {ital e}}={minus}600.
Abdullah, K.; Carlberg, C.; Commins, E.D.; Gould, H.; Ross, S.B. (Chemical Sciences Division, Building 71-259, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA (USA) Department of Physics, University of California, Berkeley, CA (USA))
The Small Magellanic Cloud (SMC) has surprisingly strong submillimeter- and millimeter-wavelength emission that is inconsistent with standard dust models, including those with emission from spinning dust. Here, we show that the emission from the SMC may be understood if the interstellar dust mixture includes magnetic nanoparticles, emitting magnetic dipole radiation resulting from thermal fluctuations in the magnetization. The magnetic grains can be metallic iron, magnetite Fe{sub 3}O{sub 4}, or maghemite {gamma}-Fe{sub 2}O{sub 3}. The required mass of iron is consistent with elemental abundance constraints. The magnetic dipole emission is predicted to be polarized orthogonally to the normal electric dipole radiation if the nanoparticles are inclusions in larger grains. We speculate that other low-metallicity galaxies may also have a large fraction of the interstellar Fe in magnetic materials.
Draine, B. T.; Hensley, Brandon, E-mail: email@example.com [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States)
Relativistic unitary coupled-cluster study of the electric quadrupole moment and magnetic dipole hyperfine constants of {sup 199}Hg{sup +}
Searching for an accurate optical clock which can serve as a better time standard than the present-day atomic clock is highly demanding from several areas of science and technology. Several attempts have been made to build more accurate clocks with different ion species. In this paper, we discuss the electric quadrupole and hyperfine shifts in the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2}(F=0,m{sub F}=0){r_reversible}5d{sup 10}6s {sup 2}S{sub 1/2}(F=2,m{sub F}=0) clock transition in {sup 199}Hg{sup +}, one of the most promising candidates for next-generation optical clocks. We have applied Fock-space unitary coupled-cluster theory to study the electric quadrupole moment of the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2} state and magnetic dipole hyperfine constants of 5d{sup 9}6s{sup 2} {sup 2}D{sub 3/2,5/2} and 5d{sup 10}6s{sup 1} {sup 2}S{sub 1/2} states, respectively, of {sup 199}Hg{sup +}. We have also compared our results with available data. To the best of our knowledge, this is the first time a variant of coupled-cluster theories has been applied to study these kinds of properties of Hg{sup +} and is the most accurate estimate of these quantities to date.
Sur, Chiranjib; Chaudhuri, Rajat K. [Department of Astronomy, Ohio State University, Columbus, Ohio 43210 (United States); Indian Institute of Astrophysics, Koramangala, Block II, Bangalore 560 034 (India)
We have shown that the study of dipole moments, both magnetic and electric, in storage rings offer unique opportunities in probing physics beyond the Standard Model (SM). Both methods use similar techniques (particle and spin precession in magnetic storage rings). We are currently investigating the systematic errors associated with the resonance electric dipole moment (EDM) method. So far it looks very promising.
Electric dipole moments (EDM) of ionic atoms
Recent investigations show that the second-order perturbation calculations of electric dipole moments (EDM) from the finite nuclear size as well as the relativistic effects are all canceled out by the third-order perturbation effects and that this is due to electron screening. To derive the nucleon EDM from the nucleus, we propose to measure the EDM of an ionic system. In this case, it is shown that the nucleon EDM can survive by the reduction factor of 1/Z for the ionic system with one electron stripped off.
Oshima, Sachiko [Department of Physics, Faculty of Science and Technology, Nihon University, Tokyo (Japan)
Dipole magnet for use of RHIC EBIS HEBT line.
Construction and magnetic field measurement of dipole magnets for RHIC-EBIS HEBT line have completed. These magnets will be used to guide highly charged ion beams ranging from proton to Uranium provided by a new injector toward the Booster ring in BNL. In this paper, overview of the magnetic design of the dipoles and results of magnetic field measurement are summarized.
Kanesue,T.; Okamura, M.; Ritter, J.; Raparia, D.
SSC collider dipole magnets field angle data
In the fabrication of both 40 and 50 mm collider dipole superconducting magnets, surveys of the direction of the magnetic field along their length have been taken. This data besides being used for certifying compliance with the specifications for the finished magnet, yields interesting information on the straightness and rigidity of the coil placement between some stages in their manufacture and testing. A discussion on the measuring equipment and procedures is given. All of the 40 mm magnets that were built or cryostat at Fermilab have at least one of these surveys, and a summary of the data on them is presented. Most of the 50 mm magnets built and cold tested at Fermilab have been surveyed before and after insertion in the cryostat and before and after being cold tested. A summary of this data is also presented.
Kuchnir, M.; Bleadon, M.; Schmidt, E.; Bossert, R.; Carson, J.; Delchamps, S.W.; Gourlay, S.; Hanft, R.; Koska, W.; Lamm, M.J.; Mazur, P.O.; Orris, D.; Ozelis, J.; Strait, J.; Wake, M. (Fermi National Accelerator Lab., Batavia, IL (United States)); DiMarco, J.; Devred, A.; Kuzminski, J.; Yu, Y.; Zheng, H. (Superconducting Super Collider Lab., Dallas, TX (United States)); Ogitsu, T. (Superconducting Super Collider
Ac loss measurement of SSC dipole magnets
AC losses in full length and 1.5 m model SSC collider dipoles were successfully measured by the direct observation of energy flow into and out of magnets during a ramp cycle. The measurement was performed by using two double-integrating type digital volt meters (DVM`s) for current and voltage measurement. Measurements were performed for six is m long ASST magnets and five 1.5 m long model magnets, inducting one 40 mm diameter magnet. There were large variations in the eddy current losses. Since these magnets use conductors with slight deviations in their internal structures and processing of the copper surface depending on the manufacturer, it is likely that there are differences in the contact resistance between strands. Correlation between the ramp rate dependence of the,quench current and the eddy current loss was evident.
Delchamps, S.; Hanft, R.; Jaffery, T.; Kinney, W.; Koska, W.; Lamm, M.J.; Mazur, P.O.; Orris, D.; Ozelis, J.P.; Strait, J.; Wake, M.
Dipole-sheet multipole magnets for accelerators
The dipole-sheet formalism can be used to describe both cylindrical current-sheet multipole magnets and cylindrical-bore magnets made up of permanent magnet blocks. For current sheets, the formalism provides a natural way of finding a finite set of turns that approximate a continuous distribution. The formalism is especially useful In accelerator applications where large-bore, short, high-field-quality magnets that are dominated by fringe fields are needed. A further advantage of the approach is that in systems with either open or cylindrically symmetric magnetic boundaries, analytical expressions for the three-dimensional fields that are suitable for rapid numerical evaluation can be derived. This development is described in some detail. Also, recent developments in higher-order particle-beam optics codes based on the formalism are described briefly.
Walstrom, P.L.
Electrically driven vortices in multipolar magnetic fields
The flow generated in a thin layer of an electrically conducting fluid by the interaction of a steady, uniform electric current with a superposition of dipolar permanent magnets, is studied experimentally and theoretically. The experiment is carried out in a rectangular plexiglass cell with a shallow layer of an electrolytic solution. Small permanent magnets are placed externally in the central part of the cell bottom in an array that may include one, two or four dipole magnets. The direct electric current which is injected thorugh two opposite walls (copper electrodes) interacts with the magnetic field distribution generating a Lorentz force that drives different vortex patterns depending on the number of dipoles, their location and the orientation of their magnetic dipole moment. The theoretical two-dimensional model that describes the flow produced by a single dipole magnet, providing non-linear convective effects are neglected, is extended to consider the influence of additional magnets.
Cuevas, Sergio
Asymmetry of Neoclassical Transport by Dipole Electric Field
Effects of dipole electric fields on neoclassical transport are studied. Large asymmetry in transport is created. The dipole fields, which are in a negative R-direction, reduce the ion drift, increase electron drift, and change the steps of excursion due to collisions. It is found that different levels of dipole field intensities have different types of transport. For the lowest level of the dipole field, the transport returns to the neoclassical one. For the highest level of the dipole field, the transport is turned to be the turbulence transport similar to the pseudo-classical transport. Experimental data may be corresponded to a large level of the dipole field intensity.
Wang, Zhongtian; Wang, Long
Magnetic field properties of SSC model dipole magnets
SSC 1.5m model dipole magnets were built and tested at Fermilab. Magnetic field properties were studied in term of transfer function variation and multipole components. The results were satisfactory. Observation of periodicity of remanent field along the axis is also reported.
Wake, M.; Bossert, R.; Carson, J.; Delchamps, S.; Jaffery, T.S.; Kinney, W.; Koska, W.; Lamm, M.J.; Strait, J. (Fermi National Accelerator Lab., Batavia, IL (United States)); Butteris, J.; Sims, R.; Winters, M. (Superconducting Super Collider Lab., Dallas, TX (United States))
Magnetostatic potential theory and the lunar magnetic dipole field
The lunar magnetic dipole moment is discussed. It is proposed that if a primordial core magnetic field existed, it would give rise to a present day nonzero external dipole magnetic field. This conclusion is based on the assumption that the lunar mantle is at least slightly ferromagnetic, and thus would maintain a permanent magnetization after the disappearance of the core
M. L. Goldstein
We investigate the effect of a distorted neutron star dipole magnetic field on pulsar pair cascade multiplicity and pair death lines. Using a simple model for a distorted dipole field that produces an offset polar cap (PC), we derive the accelerating electric field above the PC in space-charge-limited flow. We find that even a modest azimuthally asymmetric distortion can significantly increase the accelerating electric field on one side of the PC and, combined with a smaller field line radius of curvature, leads to larger pair multiplicity. The death line for producing pairs by curvature radiation moves downward in the P-P-dot diagram, allowing high pair multiplicities in a larger percentage of the radio pulsar population. These results could have important implications for the radio pulsar population, high energy pulsed emission, and the pulsar contribution to cosmic ray positrons.
Harding, Alice K.; Muslimov, Alex G.
Prospects for 10T accelerator dipole magnets
A next-generation major accelerator will require the highest possible field to minimize the circumference; however, there have been no proven designs for suitable magnets with fields substantially higher than 5T. A number of successful 4 to 5T dipole magnets have been built in recent years; these have involved long and difficult development projects. The 3'' bore 4.25T magnets for the Doubler are being produced by the hundreds at Fermilab, and a number of prototypes of the 5.2'' bore 5T ISABELLE magnets have been built. Successful short, approx. 5T models have been made at SACLAY, KEK, and Serpukhov, and a number of model magnets with lower fields have been built at many laboratories. Field uniformity achieved in these magnets is about ..delta..B/B approx. = 10/sup -3/. 10T magnets with higher field uniformity will be a challenging development task. The general problems of high-field (10T) magnets are discussed in terms of superconductor performance and mechanical limitations.
Taylor, C.E.; Meuser, R.B.
Fracture detection using a grounded subsurface vertical electric dipole
In this paper we study the scattered magnetic field above the surface of the earth due to a buried sheet-like conductor excited by a grounded and oscillating vertical electric dipole (G.V.E.D.) in the earth. The significance of this technique for the detection of water-filled fractures is that there is no magnetic field in the air, assuming that the displacement current is negligible, so long as the G.V.E.D. source is buried in a layered half-space. If any signal is detected it must be due to the presence of a 2-D or 3-D inhomogeneity, such as a sheet-like conductor. Using a numerical modeling approach, we calculated the strength and anomaly shape of the secondary magnetic field from the sheet to determine a G.V.E.D. is a suitable source detecting a major conductive fracture zone.
Zhou, Q.; Lee, K.H.; Goldstein, N.E.; Morrison, H.F.; Becker, A.
Search for the Neutron Electric Dipole Moment
Searches for the neutron electric dipole moment (EDM) are motivated by their highly suppressed Standard Model value. The observation of a non-zero signal in the next generation of experiments would point unambiguously to the existence of new physics beyond the Standard Model. Several ongoing efforts worldwide hold the potential for an up to two-orders-of-magnitude improvement beyond the current upper limit on the neutron EDM of 2.9x10{sup -6} e-cm. In this talk, I review the basic measurement principles of neutron EDM searches, then discuss a new experiment to be carried out in the United States at the Spallation Neutron Source with ultracold neutrons and an in-situ '3He''co-magnetometer'.
Plaster, Brad [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States)
Experimental Distinction of Electric and Magnetic Transition Moments. (Reannouncement with New Availability Information).
Vibronic electric and magnetic dipole transitions have the same rotational structure and relative intensity patterns , so that rotational band structure cannot distinguish parallel electric and magnetic dipole transitions. The point group symmetry of para...
D. M. Jonas S. A. Aolina R. W. Field R. J. Silbey
The neutron electric dipole moment and the Weinberg mechanism
We gave an overview of various mechanism for CP violation paying special attention to their prediction of the neutron electric dipole moment. The implication of the recent developments associated with the color electric dipole moment of gluon in various models of CP-violation are then critically assessed. 25 refs.
Electric dipole moment of the electron and of the neutron
It is shown that if Higgs-boson exchange mediates CP violation a significant electric dipole moment for the electron can result. Analogous effects can contribute to the neutron's electric dipole moment at a level competitive with Weinberg's three-gluon operator.
Barr, S. M.; Zee, A.
Dynamic dipole tracing of electric sources in the human brain
Electric generators of an EEG are well approximated by a single current dipole when they are localized in the brain. The location and vector moment of this equivalent current dipole was estimated from scalp potentials measured with 16 to 32 electrodes arranged on the scalp, where the realistic head model with uniform, homogeneous electric conductivity was used for numerical calculations.
T. Musha
Magnetic dipole discharges. I. Basic properties
A simple discharge is described which uses a permanent magnet as a cold cathode and the metallic chamber wall as an anode. The magnet's equator is biased strongly negative, which produces secondary electrons due to the impact of energetic ions. The emitted electrons are highly confined by the strong dipolar magnetic field and the negative potential in the equatorial plane of the magnet. The emitted electrons ionize near the sheath and produce further electrons, which drift across field lines to the anode while the nearly unmagnetized ions are accelerated back to the magnet. A steady state discharge is maintained at neutral pressures above 10{sup ?3} mbar. This is the principle of magnetron discharges, which commonly use cylindrical and planar cathodes rather than magnetic dipoles as cathodes. The discharge properties have been investigated in steady state and pulsed mode. Different magnets and geometries have been employed. The role of a background plasma has been investigated. Various types of instabilities have been observed such as sheath oscillations, current-driven turbulence, relaxation instabilities due to ionization, and high frequency oscillations created by sputtering impulses, which are described in more detail in companion papers. The discharge has also been operated in reactive gases and shown to be useful for sputtering applications.
Stenzel, R. L.; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States); Teodorescu-Soare, C. T.; Ionita, C.; Schrittwieser, R. [Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck (Austria)] [Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck (Austria)
Electron electric dipole moment experiment using electric-fieldquantized slow cesium atoms
A proof-of-principle electron electric dipole moment (e-EDM)experiment using slow cesium atoms, nulled magnetic fields, and electricfield quantization has been performed. With the ambient magnetic fieldsseen by the atoms reduced to less than 200 pT, an electric field of 6MV/m lifts the degeneracy between states of unequal lbar mF rbar and,along with the low (approximately 3 m/s) velocity, suppresses thesystematic effect from the motional magnetic field. The low velocity andsmall residual magnetic field have made it possible to induce transitionsbetween states and to perform state preparation, analysis, and detectionin regions free of applied static magnetic and electric fields. Thisexperiment demonstrates techniques that may be used to improve the e-EDMlimit by two orders of magnitude, but it is not in itself a sensitivee-EDM search, mostly due to limitations of the laser system.
Amini, Jason M.; Munger Jr., Charles T.; Gould, Harvey.
A spatio-temporal dipole simulation of gastrointestinal magnetic fields.
We have developed a simulation of magnetic fields from gastrointestinal (GI) smooth muscle. Current sources are modeled as depolarization dipoles at the leading edge of the isopotential ring of electrical control activity (ECA) that is driven by coupled cells in the GI musculature. The dipole moment resulting from the known transmembrane potential distribution varies in frequency and phase depending on location in the GI tract. Magnetic fields in a homogeneous volume conductor are computed using the law of Biot-Savart and characterized by their spatial and temporal variation. The model predicts that the natural ECA frequency gradient may be detected by magnetic field detectors outside the abdomen. It also shows that propagation of the ECA in the gastric musculature results in propagating magnetic field patterns. Uncoupling of gastric smooth muscle cells disrupts the normal magnetic field propagation pattern. Intestinal ischemia, which has been experimentally characterized by lower-than-normal ECA frequencies, also produces external magnetic fields with lower ECA frequencies. PMID:12848351
Bradshaw, L Alan; Myers, Andrew; Wikswo, John P; Richards, William O
Magnetic Field Properties of Fermilab Energy Saver Dipoles
At Fermilab the authors have operated a production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver\\/Doubler. At any one time 772 of these dipoles are installed in the accelerator and 62 in beamlines; the remainder are spares. Magnetic field data are now available for most of these dipoles; in this paper
R. Hanft; B. C. Brown; W. E. Cooper; D. A. Gross; L. Michelotti; E. E. Schmidt; F. Turkot
Communication: permanent dipoles contribute to electric polarization in chiral NMR spectra.
Nuclear magnetic resonance spectroscopy is blind to chirality because the spectra of a molecule and its mirror image are identical unless the environment is chiral. However, precessing nuclear magnetic moments in chiral molecules in a strong magnetic field induce an electric polarization through the nuclear magnetic shielding polarizability. This effect is equal and opposite for a molecule and its mirror image but is small and has not yet been observed. It is shown that the permanent electric dipole moment of a chiral molecule is partially oriented through the antisymmetric part of the nuclear magnetic shielding tensor, causing the electric dipole to precess with the nuclear magnetic moment and producing a much larger temperature-dependent electric polarization with better prospects of detection. PMID:24410214
Buckingham, A David
The ACME electron electric dipole moment search
Observation of a non-zero electric dipole moment (EDM) of the electron, de, within a few orders of magnitude of the current limit |de| < 1.05 x10-27 e.cm would be an indication of CP violation in physics beyond the Standard Model. Numerous extensions to the Standard Model predict a value of de in this range. The ACME Collaboration is searching for an electron EDM, by performing a precision measurement of spin precession signals from electrons in thorium monoxide (ThO) molecules. In this molecule, the EDM experiences a large electric field (� 00 GV/cm) that amplifies the spin precession. In addition, several properties of the molecular state make it possible to suppress many anticipated sources of systematic error. Our experiment uses a slow, cryogenic molecular beam to achieve unprecedented statistical accuracy. We now routinely take data with a 1? statistical uncertainty of ?de 1.0-1.5 x10-28/?T e.cm, where T is the running time in days. We will present the current status of the experiment.
Demille, David
Pair Cascades and Deathlines in Offset Magnetic Dipole Fields
We investigate electron-positron pair cascades in a dipole magnetic field whose axis is offset from the neutron star center. In such a field geometry, the polar cap is displaced from the neutron star symmetry axis and the field line radius of curvature is modified. Using the modified parallel electric field near the polar cap of an offset dipole, we simulate pair cascades to determine the pair deathlines and pair multiplicities as a function of the offset parameter. We find that the pair multiplicity can change dramatically with a modest offset, with a significant increase on one side of the polar cap. Lower pair deathlines allow a larger fraction of the pulsar population, that include old and millisecond pulsars, to produce cascades with high multiplicity.
Harding, Alice; Muslimov, Alex
Space propulsion by fusion in a magnetic dipole
The unique advantages of fusion rocket propulsion systems for distant missions are explored using the magnetic dipole configurations as an example. The dipole is found to have features well suited to space applications. Parameters are presented for a system producing a specific power of kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power performance than nuclear electric fission systems. Possibilities to further increase the specific power toward 10 kW/kg are discussed, as is an approach to implementing the concept through proof-testing on the moon. 20 refs., 14 figs., 2 tabs.
Teller, E.; Glass, A.J.; Fowler, T.K. (Lawrence Livermore National Lab., CA (United States)); Hasegawa, A. (AT and T Bell Labs., Murray Hill, NJ (United States)); Santarius, J.F. (Wisconsin Univ., Madison, WI (United States). Fusion Technology Inst.)
The lunar magnetic dipole moment is discussed. It is proposed that if a primordial core magnetic field existed, it would give rise to a present day nonzero external dipole magnetic field. This conclusion is based on the assumption that the lunar mantle is at least slightly ferromagnetic, and thus would maintain a permanent magnetization after the disappearance of the core magnetic field. Using a simple mathematical model of the moon, calculations are performed which support this hypothesis.
Goldstein, M. L.
Electric-Dipole-Induced Universality for Dirac Fermions in Graphene
We study electric dipole effects for massive Dirac fermions in graphene and related materials. The dipole potential accommodates towers of infinitely many bound states exhibiting a universal Efimov-like scaling hierarchy. The dipole moment determines the number of towers, but there is always at least one tower. The corresponding eigenstates show a characteristic angular asymmetry, observable in tunnel spectroscopy. However, charge transport properties inferred from scattering states are highly isotropic.
De Martino, Alessandro; Kl�pfer, Denis; Matrasulov, Davron; Egger, Reinhold
Electric dipole polarizability and the neutron skin
The recent high-resolution measurement of the electric dipole (E1) polarizability ?D in 208Pb [A. Tamii , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.062502 107, 062502 (2011)] provides a unique constraint on the neutron-skin thickness of this nucleus. The neutron-skin thickness rskin of 208Pb is a quantity of critical importance for our understanding of a variety of nuclear and astrophysical phenomena. To assess the model dependence of the correlation between ?D and rskin, we carry out systematic calculations for 208Pb, 132Sn, and 48Ca based on the nuclear density functional theory using both nonrelativistic and relativistic energy density functionals. Our analysis indicates that whereas individual models exhibit a linear dependence between ?D and rskin, this correlation is not universal when one combines predictions from a host of different models. By averaging over these model predictions, we provide estimates with associated systematic errors for rskin and ?D for the nuclei under consideration. We conclude that precise measurements of rskin in both 48Ca and 208Pb�combined with the recent measurement of ?D�should significantly constrain the isovector sector of the nuclear energy density functional.
Piekarewicz, J.; Agrawal, B. K.; Col�, G.; Nazarewicz, W.; Paar, N.; Reinhard, P.-G.; Roca-Maza, X.; Vretenar, D.
Nuclear Electric Dipole Moment of 3He
A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of {sup 3}He and the expected sensitivity of such a measurement to the underlying CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {pi}-, {rho}-, and {omega}-exchanges, we find that the pion-exchange contribution dominates. Finally, our results suggest that a measurement of the {sup 3}He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.
Stetcu, I; P.Liu, C; Friar, J L; Hayes, A C; Navratil, P
The search for permanent electric dipole moments
Permanent electric dipole moments (EDMs) of fundamental systems with spin - particles, nuclei, atoms or molecules violate parity and time reversal invariance. Invoking the CPT theorem, time reversal violation implies CP violation. Although CP-violation is implemented in the standard electro-weak theory, EDM generated this way remain undetectably small. However, this CP-violation also appears to fail explaining the observed baryon asymmetry of our universe. Extensions of the standard theory usually include new sources of CP violation and often predict sizeable EDMs. EDM searches in different systems are complementary and various efforts worldwide are underway and no finite value has been established yet. The prototype of an EDM search is the pursuit of the EDM of the neutron. It has the longest history and at the same time is at the forefront of present research. The talk aims at giving an overview of the field with emphasis on our efforts within an international collaboration at PSI, nedm.web.psi.ch.
Kirch, Klaus [PSI-Villigen - ETH Z�rich
Test Results for LHC Insertion Region Dipole Magnets.
The Superconducting Magnet Division at Brookhaven National Laboratory (BNL) has made 20 insertion region dipoles for the Large Hadron Collider (LHC) at CERN. These 9.45 m-long, 8 cm aperture magnets have the same coil design as the arc dipoles now operati...
J. Muratore A. Jain M. Anerella J. Cozzolino G. Ganetis A. Ghosh R. Gupta
Variable-field permanent-magnet dipole for accelerators.
A new concept for a variable-field permanent-magnet dipole has been developed and fabricated at Los Alamos. The application requires an extremely uniform dipole field in the magnet aperture and precision variability over a large operating range. An iron-c...
R. H. Kraus D. B. Barlow R. Meyer
Helical dipole magnets for polarized protons in RHIC
Superconducting helical dipole magnets will be used in the Brookhaven Relativistic Heavy Ion Collider (RHIC) to maintain polarization of proton beams and to perform localized spin rotations at the two major experimental detector regions. Requirements for the helical dipole system are discussed, and magnet prototype work is reported.
Syphers, M.; Courant, E.; Fischer, W. [and others
Extensive power tests of the LHC dipole magnets required the development of new techniques to study the quench and training behaviour. Magnetic measurements of short and long model dipoles have allowed to understand and quantify the time dependent behaviour of the field quality during the current flat top needed during beam injection. The experience gained is employed for the design
L. Walckiers; Z. Ang; J. Billan; L. Bottura; A. Siemko; P. Sievers; R. Wolf
Motion of a charged particle in the magnetic dipole field
This note discusses the motion of a charged particle in the magnetic dipole\\u000afield and a modified Barut's lepton mass formula. It is shown that a charged\\u000aparticle in the magnetic dipole filed has no bound states, which means that\\u000aBarut's lepton mass formula may have no physical basis.
Jian Qi Shen
This note discusses the motion of a charged particle in the magnetic dipole field and a modified Barut's lepton mass formula. It is shown that a charged particle in the magnetic dipole filed has no bound states, which means that Barut's lepton mass formula may have no physical basis.
Demonstration of current drive by a rotating magnetic dipole field
A dipole-like rotating magnetic field was produced by a pair of circular, orthogonal coils inside a metal vacuum chamber. When these coils were immersed in plasma, large currents were driven outside the coils: the currents in the plasma were generated and sustained by the rotating magnetic dipole (RMD) field. The peak RMD-driven current was at roughly two RMD coil radii,
L. Giersch; J. T. Slough; R. Winglee
Measurements of sextupole decay and snapback in Tevatron dipole magnets
To help optimize the performance of the Fermilab Tevatron accelerator in Collider Run II, we have undertaken a systematic study of the drift and subsequent snapback of dipole magnet harmonics. The study has mostly focused on the dynamic behavior of the normal sextupole component, b2, as measured on a sample of spare Tevatron dipoles at the Fermilab Magnet Test Facility.
Gueorgui V. Velev; G. Annala; P. Bauer; R. Carcagno; J. DiMarco; H. Glass; R. Hanft; R. Kephart; M. Lamm; M. Martens; P. Schlabach; C. Sylvester; M. Tartaglia; J. Tompkins
The electric dipole moment of cobalt monoxide, CoO
A number of low-rotational lines of the E4?7/2 ? X4?7/2 (1,0) band system of cobalt monoxide, CoO, were recorded field free and in the presence of a static electric field. The magnetic hyperfine parameter, h7/2, and the electron quadrupole parameter, eQq0, for the E4?7/2(? = 1) state were optimized from the analysis of the field-free spectrum. The permanent electric dipole moment, ?c ? _{el}, for the X4?7/2 (? = 0) and E4?7/2 (? = 1) states were determined to be 4.18 � 0.05 D and 3.28 � 0.05 D, respectively, from the analysis of the observed Stark spectra of F' = 7 ? F? = 6 branch feature in the Q(7/2) line and the F' = 8 ? F? = 7 branch feature in the R(7/2) line. The measured dipole moments of CoO are compared to those from theoretical predictions and the trend across the 3d-metal monoxide series discussed.
Zhuang, Xiujuan; Steimle, Timothy C.
Shell-model study of electric dipole and spin-dipole strengths in 11Li
We have studied electric dipole (E1) and spin-dipole strength distribution in 11Li by shell model calculations with halo effect. Two peaks in the E1 strength are found in the low excitation energy region below Ex=4 MeV, which have almost the same energies as observed E1 peaks in the Coulomb breakup reaction of 11Li. The calculated E1 strength up to Ex=4 MeV exhaust about 4% of the Thomas-Reiche-Kuhn energy-weighted sum rule value. We found also pigmy and giant peaks in spin-dipole strengths of 11Li. Possible existence of double soft dipole mode and giant resonance built on the soft dipole states are investigated.
Suzuki, Toshio; Sagawa, H.; Bortignon, P. F.
Colored scalars and the neutron electric dipole moment
We investigate new contributions to the neutron electric dipole moment induced by colored scalars. As an example, we evaluate contributions coming from the color octet, weak doublet scalar, accommodated within a modified minimal flavor-violating framework. These flavor nondiagonal couplings of the color octet scalar might account for the measured asymmetry aCP(D0?K-K+)-aCP(D0??+?-) at tree level. The same couplings constrained by this asymmetry also induce two-loop contributions to the neutron electric dipole moment. We find that the direct CP-violating asymmetry in neutral D-meson decays is more constraining on the allowed parameter space than the current experimental bound on the neutron electric dipole moment. We comment also on contributions of higher-dimensional operators to the neutron electric dipole moment within this framework.
Fajfer, Svjetlana; Eeg, Jan O.
Limit on the Electron Electric Dipole Moment in Gadolinium-Iron Garnet
A new method for the detection of the electron electric dipole moment (EDM) using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the sample's magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron EDM of 5x10{sup -24}e cm, which is a factor of 40 below the limit obtained from the only previous solid-state EDM experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization.
Heidenreich, B.J.; Elliott, O.T.; Charney, N.D.; Virgien, K.A.; Bridges, A.W.; McKeon, M.A.; Peck, S.K.; Krause, D. Jr.; Gordon, J.E.; Hunter, L.R.; Lamoreaux, S.K. [Physics Department, Amherst College, Amherst, Massachusetts 01002 (United States); Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Measurement of the Cesium Electric-Dipole Moment
In 1989 new limits were established on the electron edm by measuring the electric-dipole moment (edm) of atomic cesium.(S.A. Murthy, D. Krause, Jr., Z.L. Li and L.R. Hunter, Phys. Rev. Lett.63, 965 (1989).) Work on the measurement of the cesium edm has continued and a number of important improvements have been made. The current experiment uses four cells in order to subtract fluctuations in magnetic field gradients. Larger cells are used to improve the electric field homogeneity and reversibility. The cells are heated by raising the temperature of the entire magnetic shield assembly. This results in greater temperature uniformity, which reduces magnetic noise associated with thermoelectric currents. New detectors have been designed and assembled which have electronics noise well below the photon noise. These improvements have resulted in more than a factor of twenty improvement in the experiment's sensitivity. The current status of the experiment will be reviewed and the most recent data will be reported.
Hunter, Larry; Peck, Stephen; Krause, Daniel; Newman, Erica
QED vacuum fluctuations and induced electric dipole moment of the neutron
Quantum fluctuations in the QED vacuum generate nonlinear effects, such as peculiar induced electromagnetic fields. In particular, we show here that an electrically neutral particle, possessing a magnetic dipole moment, develops an induced electric dipole-type moment with unusual angular dependence, when immersed in a quasistatic, constant external electric field. The calculation of this effect is done in the framework of the Euler-Heisenberg effective QED Lagrangian, corresponding to the weak field asymptotic expansion of the effective action to one-loop order. It is argued that the neutron might be a good candidate to probe this signal of nonlinearity in QED.
Dominguez, C. A. [Centre for Theoretical Physics and Astrophysics, University of Cape Town, Rondebosch 7700 (South Africa); Department of Physics, Stellenbosch University, Stellenbosch 7600 (South Africa); Falomir, H. [Instituto de Fisica La Plata-Consejo Nacional de Ciencia y Tecnica, Universidad Nacional de La Plata (Argentina); Ipinza, M.; Loewe, M. [Facultad de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Kohler, S. [Department of Physics, Stellenbosch University, Stellenbosch 7600 (South Africa); Rojas, J. C. [Departamento de Fisica, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile)
Development of Cellular Magnetic Dipoles in Magnetotactic Bacteria
Magnetotactic bacteria benefit from their ability to form cellular magnetic dipoles by assembling stable single-domain ferromagnetic particles in chains as a means to navigate along Earth's magnetic field lines on their way to favorable habitats. We studied the assembly of nanosized membrane-encapsulated magnetite particles (magnetosomes) by ferromagnetic resonance spectroscopy using Magnetospirillum gryphiswaldense cultured in a time-resolved experimental setting. The�spectroscopic data show that 1), magnetic particle growth is not synchronized; 2), the increase in particle numbers is insufficient to build up cellular magnetic dipoles; and 3), dipoles of assembled magnetosome blocks occur when the first magnetite particles reach a stable single-domain state. These stable single-domain particles can act as magnetic docks to stabilize the remaining and/or newly nucleated superparamagnetic particles in their adjacencies. We postulate that docking is a key mechanism for building the functional cellular magnetic dipole, which in turn is required for magnetotaxis in bacteria.
Faivre, Damien; Fischer, Anna; Garcia-Rubio, Ines; Mastrogiacomo, Giovanni; Gehring, Andreas U.
Dipole-quadrupole dynamics during magnetic field reversals
The shape and the dynamics of reversals of the magnetic field in a turbulent dynamo experiment are investigated. We report the evolution of the dipolar and the quadrupolar parts of the magnetic field in the VKS experiment, and show that the experimental results are in good agreement with the predictions of a recent model of reversals: when the dipole reverses, part of the magnetic energy is transferred to the quadrupole, reversals begin with a slow decay of the dipole and are followed by a fast recovery, together with an overshoot of the dipole. Random reversals are observed at the borderline between stationary and oscillatory dynamos.
Gissinger, Christophe [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)
On the magnetic dipole fields at surface atoms
The magnetic dipole fields at atoms in small particles and thin films of alpha-Fe have been calculated. Only the dipole fields in the first surface layer are significantly affected by the presence of the surface. It is shown that the shape anisotropy energy of microcrystals is influenced by these surface effects.
Per Helvig Christensen; Steen M�rup
New experimental limit on the electric dipole moment of the electron.
We describe a search for the electric dipole moment d(sub e) of the electron, carried out with (sup 205)Tl atoms in the ground state. The experiment makes use of the separated-oscillating-field magnetic-resonance method, laser state selection, fluorescenc...
C. Carlberg H. Gould K. Abdullah E. D. Commins S. B. Ross
Solid-state systems for the electron electric dipole moment and other fundamental measurements
In 1968, Shapiro published the suggestion that one could search for an electron dipole moment (EDM) by applying a strong electric field to a substance that has an unpaired electron spin; at low temperature, the EDM interaction would lead to a net sample magnetization that can be detected with a superconducting quantum interference device (SQUID) magnetometer. One experimental EDM search
S. K. Lamoreaux
Electron capture by an electric dipole in two dimensions
The question of the existence of a nonzero minimum dipole moment D{sub 0} that can sustain an electron bound state for an electric dipole in two dimensions is examined both classically and quantum mechanically. The results suggest that in the latter case, D{sub 0}{<=}0.209 compared to the Fermi-Teller value 0.904 for three dimensions (in atomic units)
Glasser, M. L.; Nieto, L. M. [Department of Physics, Clarkson University, Potsdam, New York 13699-5820 (United States); Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, 47071 Valladolid (Spain)
Design and Procurement of the European Dipole (EDIPO) Superconducting Magnet
A 12.5 T superconducting dipole magnet (European DIPOle, EDIPO) has been designed by EFDA and it is now being procured within the framework of the European Fusion Programme in order to be installed in CRPP-PSI. This saddle-shaped magnet is designed to reach 12.5 T in a 100 times 150 mm rectangular bore over a length of about 1.5 m in
A. Portone; W. Baker; E. Salpietro; A. Vostner; P. Bruzzone; F. Cau; A. della Corte; A. Di Zenobio; E. Theisen; A. Baldini; P. Testoni; J. Lucas; M. Pinilla; G. Samuelli
Test results for a Nb3Sn dipole magnet
A cosine theta type dipole magnet using Nb3Sn conductor have been designed, built and tested. D19H is a two-layer dipole magnet with a Nb3Sn inner layer and a recycled NbTi outer layer. Coil-pairs are connected with two of the four Nb3Sn splices in a high field region, and compressed by a ring and collet system. The ramp-rate sensitivity and the
A. F. Lietzke; R. Benjegerdes; S. Caspi; D. Dell'Orco; W. Harnden; A. D. McInturff; M. Morrison; R. M. Scanlan; C. E. Taylor; J. M. van Oort
Dual aperture dipole magnet with second harmonic component
An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.
Praeg, W.F.
Praeg, Walter F. (Palos Park, IL)
Compact Electric- And Magnetic-Field Sensor
Compact sensor measures both electric and magnetic fields. Includes both short electric-field dipole and search-coil magnetometer. Three mounted orthogonally providing triaxial measurements of electromagnetic field at frequencies ranging from near 0 to about 10 kHz.
Winterhalter, Daniel; Smith, Edward
Regular and chaotic orbits near a massive magnetic dipole
Within the framework of Bonnor's exact solution describing a massive magnetic dipole, we study the motion of neutral and electrically charged test particles. In dependence on the Bonnor spacetime parameters, we determine regions enabling the existence of stable circular orbits confined to the equatorial plane and of those levitating above the equatorial plane. Constructing Poincar� surfaces of section and recurrence plots, we also investigate the dynamics of particles moving along general off-equatorial trajectories bound in effective potential wells forming around the stable circular orbits. We demonstrate that the motion in the Bonnor spacetime is not integrable. This extends previous investigations of generalized St�rmer's problem into the realm of exact solutions of Einstein-Maxwell equations, where the gravitational and electromagnetic effects play a comparable role on the particle motion.
Kov�?, Ji?�; Kop�?ek, Ond?ej; Karas, Vladim�r; Kojima, Yasufumi
A multiferroic material to search for the permanent electric dipole moment of the electron
We describe the first-principles design and subsequent synthesis of a new material with the specific functionalities required for a solid-state-based search for the permanent electric dipole moment of the electron. We show computationally that perovskite-structure europium barium titanate should exhibit the required large and pressure-dependent ferroelectric polarization, local magnetic moments and absence of magnetic ordering at liquid-helium temperature. Subsequent synthesis
K. Z. Rushchanskii; S. Kamba; V. Goian; P. Vanek; M. Savinov; J. Prokleska; D. Nuzhnyy; K. Kn�zek; F. Laufek; S. Eckel; S. K. Lamoreaux; A. O. Sushkov; M. Lezaic; N. A. Spaldin
Influence of medium chirality on electric dipole-dipole resonance energy transfer
Electric dipole-dipole resonance energy transfer taking place between two chromophores in an absorptive and dispersive chiral medium is studied. Quantized electromagnetic field operators in this environment are first obtained from the time-harmonic Maxwell equations and the Drude-Born-Fedorov equations. Second-order time-dependent perturbation theory and the Fermi Golden rule are used to calculate the transfer rate. A complicated dependence on the permittivity, permeability and chirality admittance of the medium is found. In the near-zone, the rate is amplified in a medium with negligible absorption comprised of one enantiomer relative to that in a racemic mixture.
Rodriguez, Justo J.; Salam, A.
Axisymmetric flow between differentially rotating spheres in a dipole magnetic field
Constant-density electrically conducting fluid is confined to a rapidly rotating spherical shell and is permeated by an axisymmetric potential magnetic field with dipole parity; the regions outside the shell are rigid insulators. Slow steady axisymmetric motion is driven by rotating the inner sphere at a slightly slower rate. Linear solutions of the governing magnetohydrodynamic equations are derived in the small
N. Kleeorin; I. Rogachevskii; A. Ruzmaikin; A. M. Soward; S. Starchenko
Wire dipoles and antennas with dielectric or magnetic coatings
A prescription which enables any theoretical formulation for scattering and radiation by an arbitrary bare wire antenna of circular cross section to be extended to antennas having a thin coating of dielectric or magnetic material is derived. The prescription is applied to the Harrison and Heinz (1963) treatment of a bare half-wave dipole to extend that theory to treat dielectric-coated dipoles. There is excellent agreement between the resulting theoretical predictions and measurements for the radar cross section of glass-coated copper dipoles.
Moore, J.; Scrimgeour, A. C.
Torsional oscillations of relativistic stars with dipole magnetic fields
We present the formalism and numerical results for torsional oscillations of relativistic stars endowed with a strong dipole magnetic field, assumed to be confined to the crust. In our approach, we focus on axisymmetric modes and neglect higher order couplings induced by the magnetic field. We do a systematic search of parameter space by computing torsional mode frequencies for various
H. Sotani; K. D. Kokkotas; N. Stergioulas
Measuring magnetic dipole fields using Hall effects sensors
The way in which a Hall effect transducer is made appropriate for measuring magnetic fields is described. The aim of this is to provide a thermally well compensated probe that gives precise orientation and positioning for taking measurements. This probe is used in the checking of far fields generated by magnetic dipoles.
L. Benadero; J. A. Gorri; J. Villar; A. Albareda; E. Toribio; R. Perez
Insolubility of trapped particle motion in a magnetic dipole field
Topological and numerical techniques are used to show that the problem of trapped charged particle motion in a magnetic dipole field is insoluble. Similar results hold for motion in the earth's magnetic field and are of interest for radiation belt phenomena. Pedagogical discussion is devoted to the subject of how it can happen that a classical mechanics problem is insoluble
A. J. Dragt; J. M. Finn
Magnetic fluids - suspensions of magnetic dipoles and their magnetic control
Suspensions of magnetic nanoparticles exhibit normal liquid behaviour coupled with superparamagnetic properties. This leads to the possibility to control the properties and the flow of these liquids with moderate magnetic fields. The magnetic control enables various experiments in fluid mechanics and gives rise to the development of numerous technical and medical applications. Ferrofluids and their general properties will be introduced
S. Odenbach
Baryogenesis, electric dipole moments and dark matter in the MSSM
We study the implications for electroweak baryogenesis (EWB) within the minimal supersymmetric Standard Model (MSSM) of present and future searches for the permanent electric dipole moment (EDM) of the electron, for neutralino dark matter, and for supersymmetric particles at high energy colliders. We show that there exist regions of the MSSM parameter space that are consistent with both present two-loop
Vincenzo Cirigliano; Stefano Profumo; Michael J. Ramsey-Musolf
Enhancement of the electron electric dipole moment in gadolinium garnets
Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve the current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. Our calculation accounts for both direct and exchange diagrams.
Mukhamedjanov, T.N.; Dzuba, V.A.; Sushkov, O.P. [School of Physics, University of New South Wales, Sydney 2052 (Australia)
Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve the current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. Our calculation accounts for both direct
T. N. Mukhamedjanov; V. A. Dzuba; O. P. Sushkov
Elf and VLF Fields of a Horizontal Electric Dipole.
The waves in the spherical guide between the earth and ionosphere are excited by a horizontal electric dipole. The guide boundaries are characterized by surface impedances, and the resulting waves are expressed as a superposition of TM and TE modes. The w...
J. Galejs
Search for the Electric Dipole of the Electron.
We report a new upper limit on the electric dipole moment (EDM) of the electron of d(sub e) = 0.1 (plus minus) 3.2 (times) 10(sup (minus)26) e-cm. This precision is one hundred times better than any previously published limit and a factor of two better th...
K. F. Abdullah
Complete electric dipole response and the neutron skin in 208Pb.
A benchmark experiment on (208)Pb shows that polarized proton inelastic scattering at very forward angles including 0� is a powerful tool for high-resolution studies of electric dipole (E1) and spin magnetic dipole (M1) modes in nuclei over a broad excitation energy range to test up-to-date nuclear models. The extracted E1 polarizability leads to a neutron skin thickness r(skin) = 0.156(-0.021)(+0.025) fm in (208)Pb derived within a mean-field model [Phys. Rev. C 81, 051303 (2010)], thereby constraining the symmetry energy and its density dependence relevant to the description of neutron stars. PMID:21902316
Tamii, A; Poltoratska, I; von Neumann-Cosel, P; Fujita, Y; Adachi, T; Bertulani, C A; Carter, J; Dozono, M; Fujita, H; Fujita, K; Hatanaka, K; Ishikawa, D; Itoh, M; Kawabata, T; Kalmykov, Y; Krumbholz, A M; Litvinova, E; Matsubara, H; Nakanishi, K; Neveling, R; Okamura, H; Ong, H J; Ozel-Tashenov, B; Ponomarev, V Yu; Richter, A; Rubio, B; Sakaguchi, H; Sakemi, Y; Sasamoto, Y; Shimbara, Y; Shimizu, Y; Smit, F D; Suzuki, T; Tameshige, Y; Wambach, J; Yamada, R; Yosoi, M; Zenihiro, J
An alternate method for designing dipole magnet ends
Small bore superconducting dipole magnets, such as those for the SSC, often have problems in the ends. These problems can often be alleviated by spreading out the end windings so that the conductor sees less deformation. This paper presents a new procedure for designing dipole magnet ends which can be applied to magnets with either cylindrical or conical bulged ends to have integrated field multipoles which meet the constraints imposed by the SSC lattice. The method described here permits one to couple existing multiparameter optimization routines (i.e., MINUIT with suitable independent parameter constraints) with a computer code DIPEND, which describes the multiples, so that one can meet any reasonable objective (i.e., minimizing integrated sextupole and decapole). This paper will describe how the computer method was used to analyze the bulged conical ends for an SSC dipole. 6 refs, 6 figs, 2 tabs.
Pope, W.L.; Green, M.A.; Peters, C.; Caspi, S.; Taylor, C.E.
Tunable interactions between vortices and a magnetic dipole
The interactions between vortices in a thin superconducting film and one magnetic dipole in the presence of a magnetic field applied parallel to the film surfaces are studied theoretically in the London limit. The dipole magnetic moment is assumed to have constant magnitude and freedom to rotate. The pinning potential for an arbitrary vortex configuration is calculated exactly. It is found that, due to the dipole freedom to rotate, the pinning potential differs significantly from that for a permanent dipole. In particular, its dependence on the applied field is nontrivial and allows for tuning of the pinning potential by the applied field. The critical current for one vortex pinned by the dipole is obtained numerically as a function of the applied field and found to depend strongly on the field. Order of magnitude changes in the critical current resulting from changes in the direction and magnitude of the applied field are reported, with discontinuous changes taking place in some cases. The effect of vortex pinning by random material defects on the critical current is investigated using a simple model. It is found that if random pinning is weak the critical current remains strongly dependent on the applied field. Possible applications to vortices pinned by arrays of magnetic dots are briefly considered.
Carneiro, Gilson
Magnets and Electricity - Creating Magnetism with Electricity
NSDL National Science Digital Library
This cooperative classroom activity will allow students to apply their knowledge of magnetism and electricity. The students will create a circuit that lights a flashlight bulb and simultaneously practice the skills of prediction, observation, inferrence, recording, investigation and communication.
Magnetic-Field Considerations in Superferric Dipole.
Iron dominated magnets are characterized in the limit of infinite permeability by a pole shape that is a magnetic equipotential. Deviations from this ideal because of finite permeability are associated with differences in path length, local saturation, fl...
S. C. Snowdon
Near-Field Magnetic Dipole Moment Analysis.
This paper describes the data analysis technique used for magnetic testing at the NASA Goddard Space Flight Center (GSFC). Excellent results have been obtained using this technique to convert a spacecraft s measured magnetic field data into its respective...
P. K. Harris
An ancient lunar magnetic dipole field
Theories giving the source of the previously hypothesized ancient strong lunar magnetic field and reasons for its disappearance are presented. It is suggested that since it was demonstrated that the moon possessed a small iron core, a dynamo process within this core may have accounted for the field. The disappearance of this magnetizing field can be explained; either the magnetic
S. K. Runcorn
An update on passive correctors for the SSC dipole magnets
The concept of correction of the magnetization sextupole became a topic of discussion as soon as it was realized that superconductor magnetization could have a serious effect on the SSC beam during injection. Several methods of correction were proposed. These included (1) correction with active bore tube windings like those on the HERA machine which correct out magnetization sextupole and the sextupole due to iron saturation, (2) correction with persistent sextupole windings mounted on the bore tube (3) correction using passive superconductor (4) correction using ferromagnetic material, and (5) correction using oriented magnetized materials. This report deals with the use of passive superconductor to correct the magnetization sextupole. Two basic methods are explored in this report: (1) One can correct the magnetization sextupole by changing the diameter of the superconductor filaments in one or more blocks of the SSC dipole. (2) One can correct the magnetization sextupole and decapole by mounting passive superconducting wires on the inside of the SSC dipole coil bore. In addition, an assessment of the contribution of each conductor in the dipole to the magnetization sextupole and decapole is shown. 38 refs, 25 figs., 15 tabs.
Green, M.A.
The concept of correction of the magnetization sextupole became a topic of discussion as soon as it was realized that superconductor magnetization could have a serious effect on the SSC beam during injection. Several methods of correction were proposed. These included (1) correction with active bore tube windings like those on the HERA machine which correct out magnetization sextupole and the sextupole due to iron saturation, (2) correction with persistent sextupole windings mounted on the bore tube, (3) correction using passive superconductor, (4) correction using ferromagnetic material, and (5) correction using oriented magnetized materials. This report deals with the use of a passive superconductor to correct the magnetization sextupole. Two basic methods are explored in this report: (1) One can correct the magnetization sextupole by changing the diameter of the superconductor filaments in one or more blocks of the SSC dipole. (2) One can correct the magnetization sextupole and decapole by mounting passive superconducting wires on the inside of the SSC dipole coil bore. In addition, an assessment of the contribution of each conductor in the dipole to the magnetization sextupole and decapole is shown.
Green, M. A.
Dipole-exchange spin waves in magnetic nanomaterials
The aim of this thesis is to investigate the dipole-exchange spin waves in several low-dimensional ferromagnetic nanosystems. A microscopic theory is employed based on a Hamiltonian approach and a discrete lattice model. The Hamiltonian includes both the exchange and the magnetic dipole-dipole interactions, as well as the single-ion anisotropy and a Zeeman term for an externally applied magnetic field. Some of the advantages of this microscopic theory over the macroscopic methods are that it is convenient for describing the dynamical properties of samples where the magnetization may be spatially inhomogeneous, and it does not require the specification of phenomenological boundary conditions at the sample surfaces. The spin wave frequencies are obtained by employing a boson operator method with a diagonalization procedure. The spectral intensity, spin wave amplitudes and effective pinning are also studied within a Green function theory. The spin wave properties are first studied for ultrathin ferromagnetic films with simple cubic, body-centered cubic and face-centered cubic lattice structures. Results are deduced for the spin wave frequencies as a function of the in-plane wave vector, the magnetic field applied either parallel or perpendicular to the film surfaces, and the material parameters. The spin wave properties are shown to depend sensitively on the lattice structures in certain wave-vector regimes. Next we carry out spin wave calculations for individual (non-interacting) ferromagnetic stripes or wires. The numerical results are compared with the macroscopic theories and with the experimental data, where available. Then we examine the role of the long-range dipole-dipole interactions between stripes on the spin waves for two different types of stripe arrays. The coupling is found to depend on the array geometry and the direction of the applied field. Comparison of our results with experimental data (e.g., for Permalloy) shows a good agreement, confirming the role of the interstripe dipolar coupling. Finally the dipole-exchange spin waves are investigated in spherical ferromagnetic nanoparticles including spheres, spherical shells and part spheres, both singly and in finite-sized arrays. The mode-mixing (hybridization) effects on the spin wave are shown to be important, depending on the particle sizes and geometries. Keywords: spin waves, dipole-exchange theory, ferromagnets, magnetic nanomaterials, ultrathin films, magnetic stripes, magnetic arrays, magnetic spheres, magnetic nanoparticles, Brillouin light scattering, Green function theory.
Nguyen, Thi Hoa
Dynamics of nonadiabatic charged particles in the magnetic dipole field with imposed homogeneous magnetic field
The model of charged particles motion in the summary dipole and external uniform, parallel to dipole, field is considered. External field associates with the effect of magnetic perturbation. Such problem appears, for example, for protons in geomagnetic field during the magnetic storm. In contrast to traditional model, not the line of force, but the so-called Central Trajectory (CT-trajectory which passes
I. V. Amirkhanov; E. P. Zhidkov; Yu. G. Dzyuba; A. N. Ilina; V. D. Ilin
Nonadiabatic Behavior of the Magnetic Moment of a Charged Particle in a Dipole Magnetic Field.
Non-adiabatic behavior of the magnetic moment of a charged particle in a dipole magnetic field is studied both numerically and analytically in the presence of a low frequency electrostatic wave with azimuthal component. The authors obtained numerically tw...
S. Murakami T. Sato A. Hasegawa
A prescription which enables any theoretical formulation for scattering and radiation by an arbitrary bare wire antenna of circular cross section to be extended to antennas having a thin coating of dielectric or magnetic material is derived. The prescription is applied to the Harrison and Heinz (1963) treatment of a bare half-wave dipole to extend that theory to treat dielectric-coated
J. Moore; A. C. Scrimgeour
Dipole Resonances in a Homogeneous Plasma in a Magnetic Field
Radar observations recently made from a satellite orbiting above the ionosphere provide evidence for resonances of a plasma in a magnetic field which may be excited and detected by a dipole. The plasma may be said to be resonant, for a particular mode and frequency, if the group velocity is zero. These resonances are studied theoretically on the assumption that
Peter A. Sturrock
Dipole bending magnets are required to change the horizontal separation of the two beams in the LHC. In Intersection Regions (IR) 1, 2, 5, and 8, the beams are brought into collision for the experiments located there. In IR4, the separation of the beams is increased to accommodate the machine's particle acceleration hardware. As part of the US contribution to
Skew quadrupole in RHIC dipole magnets at high fields
In the RHIC are dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry
A. Jain; R. Gupta; P. Thompson; P. Wanderer
Motion of charged particles in a magnetic dipole field
A method is proposed for determining the boundary of the forbidden region for motion of charged particles in the field of a magnetic dipole when the particles begin their motion at the equator. The concept of a 'super-forbidden region' is introduced - a region in space where the Taylor series, obtained by expanding at the starting point the projection of
Iu. A. Baurov; S. N. Ogorodnikov
Resonant Alfven Waves in a Dipole Magnetic Field.
The general problem of determining the plasma density distribution in a dipole magnetic field by means of the characteristics of resonant Alfven waves is discussed in terms of the theory of Hill's differential equation. It is shown that for a spectrum of ...
Y. T. Chiu
Petrophysics of magnetic dipole fields in an anisotropic earth
Measurement-while-drilling (MWD) resistivity log data are often acquired in highly deviated or horizontal holes. The loop sensors are located on the drill collar and are approximated as magnetic dipoles. The conductivity of the earth in the vertical direction ?v and horizontal direction ?h are almost always different. When an MWD resistivity tool enters a new bed, the response is compared
Electron Waves in the Magnetic Dipole Field of a Neutron
The relativistic wave functions for an electron moving in the field of a central magnetic dipole that has spin 12ℏ are studied. Spin inertia and retardation of the central field are neglected. In general, there are then four, first-order, coupled differential equations for the radial dependence of the electron waves; and these are equivalent to two coupled Schroedinger equations having
Charles L. Critchfield
Deformation of a magnetic dipole field by trapped particles
A model for the stormtime ring current, based on a self-consistent steady state solution of Vlasov's and Maxwell's equations for a finite pressure plasma immersed in the earth's dipole field, is described. The particular choice of the particle distribution function is justified by the good fit to OGO 3 particle energy density and the Explorer 26 magnetic field measurements made
K. Lackner
A charged particle which moves spirally around a line of force of a ; magnetic dipole field is also at the same time deflected perpendicularly to the ; field. The usual relationship expressing this drift should include a third terms ; dependent on the central force. This term is derived and the relationship is ; corrected. (J.S.R.);
To help optimize the performance of the Fermilab Tevatron accelerator in Collider Run II, we have undertaken a systematic study of the drift and subsequent snapback of dipole magnet harmonics. The study has mostly focused on the dynamic behavior of the normal sextupole component, b2, as measured on a sample of spare Tevatron dipoles at the Fermilab Magnet Test Facility. We measured the dependence of the decay amplitude and the snapback time on Tevatron ramp parameters and magnet operational history. A series of beam studies was also performed [1]. This paper summarizes the magnetic measurement results and concludes with proposals for an optimization of the b2 correction scheme which is derived from these measurements.
Gueorgui V. Velev et al.
Electric dipole moment in the split supersymmetry models
We study an important contribution to the electric dipole moment (EDM) of the electron (or quarks) at the two-loop level due to the W-EDM in the recently proposed scenario of split supersymmetry. This contribution is independent of the Higgs mass, and it can enhance the previous estimation of the electron (neutron) EDM by 20-50% (40-90%). Our formula is new in its analytical form.
Chang, Darwin; Chang, W.-F.; Keung, W.-Y. [Physics Department, National TsingHua University, Hsinchu 300, Taiwan (China); Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Physics Department, University of Illinois, Chicago, Illinois 60607-7059 (United States)
Light scattering by an ensemble of interacting dipolar particles with both electric and magnetic polarizabilities
We have studied the problem of light scattering by an ensemble of dipoles with both electric and magnetic polarizabilities. Using the coupled electric and magnetic dipole method as the formal base, we have generalized the eigenvector decomposition of the local dipole moments previously derived for purely electric particles to the case of both electric and magnetic dipoles. We have analyzed the properties of eigenvalues and eigenvectors in the most elementary case of two particles. In the purely electric case, the eigenvalues correspond to the resonance modes of the system due to the electromagnetic coupling of its components. For a two-dipole system with both electric and magnetic responses, purely electric, purely magnetic, and mixed states can be distinguished. The resonance spectrum is analyzed as a function of the magnetic permeability, and it is shown that the latter can be fitted quite accurately by the eigenmode decomposition.
Merchiers, O.; Moreno, F.; Gonzalez, F.; Saiz, J. M. [Grupo de Optica, Departamento de Fisica Aplicada, Universidad de Cantabria, Avenida de los Castros, 39005 Santander (Spain)
Dipole Modeling of Magnetic Flux Leakage
In this paper, we present an analytical model to represent the 3-D magnetic flux leakage (MFL) field due to the occurrence of a surface-breaking defect in a ferromagnetic specimen. This situation is frequently encountered in the nondestructive evaluation (NDE) of energy pipelines using the MFL technique. The model is derived from first principles, and utilizes the concept of dipolar magnetic
Sushant M. Dutta; Fathi H. Ghorbel; Roderic K. Stanley
Magnetic Fields of a Dipole in Special Volume Conductor Shapes
Expressions are presented for the magnetic fields produced by current dipoles in four basic volume conductor shapes. These shapes are the semi-infinite volume, the sphere, the prolate spheroid (egg-shape), and the oblate spheroid (discus-shape). The latter three shapes approximate the shape of the human head and can serve as a basis for understanding the measurements of the brain's magnetic fields.
B. Neil Cuffin; David Cohen
A rotating solar magnetic "dipole' observed from 1926 to 1968.
A recurring pattern with a period of 26 7/8 days observed in the polar geomagnetic field during the interval from 1926 to 1941 appears to persist in the interplanetary magnetic field polarity observed with spacecraft during the interval from 1963 to 1968. This observation suggests the existence of a rotating solar magnetic ?dipole' with a period of 26 7/8 plus or minus 0.003 days.
Wilcox, J. M.; Gonzalez, W.
Coil end design for the SSC collider dipole magnet
The authors describe the design of the coil end for the 50-mm-aperture SSC (Superconducting Super Collider) dipole magnets built at Fermilab. The cable paths are determined from both magnetic and mechanical considerations. The end spacers are designed using the developable surface\\/grouped end approach, which allows the analysis of strain energy within the conductor groups. Techniques for strain energy minimization are
J. S. Brandt; N. W. Bartlett; R. C. Bossert; J. A. Carson; J. J. Konc; G. C. Lee; J. M. Cook; S. Caspi; M. A. Gordon; F. Nobrega
Four-layer, two-inch bore, superconducting dipole magnet
Superconductors provide the accelerator designer with a unique opportunity to construct machines that can achieve high particle energies and yet have low operating costs. This paper describes the design, fabrication and testing of a 4 layer, 50 mm bore superconducting dipole magnet, D-9A. The magnet reached short sample, 5.8 T at 4.4 K and 8.0 T and 1.8 K, with little training, and exhibited low losses and low ramp rate sensitivity.
Hassenzahl, W.V.; Peters, C.; Gilbert, W.; Taylor, C.; Meuser, R.
Connecting Electricity and Magnetism
As discussed at the beginning of the book, there is an intimate connection between electricity and magnetism, which will be further addressed in this chapter as well. We'll end up with a scientific model for what magnetism is, what makes something a permanent magnet, and why magnets attract some metals and not others.
Robertson, William C.
The electric dipole moments of SeH and GeH in their ground 2? states
The relative intensities of electric and magnetic dipole transitions in the fine structure spectrum of SeH in its X 2? state have been measured using the technique of laser magnetic resonance (LMR). Since the magnetic moment is known in this case, the measurements can be used to determine the molecule's electric dipole moment. The permanent electric dipole moment of SeH has been measured previously from the Stark effect (? 0 = 0483 D) it is found that a consistent interpretation of the intensities is only possible if account is taken of mixing of excited electronic states by spin�orbit coupling (incipient Hund's case (c) behaviour). Electronic transition moments make sizable contributions to the intensities. Measurements for SeH are used to estimate the electric dipole transition moment between the A 2? and X 2? states; the value obtained is ? 1 = 0.312 or -0.091 D. It seems likely that the discrepancy between the experimental and theoretical values for the permanent electric dipole moment of GeH in its X 2? state can be accounted for in the same manner.
Ashworth, Stephen H.; Brown, John M.
Contribution of W{sup {plus_minus}}H{sup {minus_plus}}Z{sub i} vertices to anomalous magnetic dipole and electric quadrupole moments of the W boson in the extra U(1) superstring-inspired model
W{sup {plus_minus}}H{sup {minus_plus}}Z{sub i} (i=1,2) vertices available exclusively in the extra U(1) superstring-inspired model have been utilized to evaluate the W-W-{gamma} vertex contribution at the one loop level. The expressions so obtained have been used to estimate the anomalous magnetic dipole moment ({Delta}k{sub WZ{sub i}H}) and electric quadrupole moment ({Delta}Q{sub WZ{sub i}H}) of the W{sup +} boson. The contribution of the Z{sub 2}WW vertex is also added to these values. The resulting values in the unit of ({minus}{alpha}/{pi}) when the Z{sub 2} mass varies from 555 to 620 GeV have the following ranges: for m{sub t(CDF)}=175.6GeV, {Delta}k{sub [U(1)]}, from 25.402 to 41.559, {Delta}Q{sub [U(1)]}, from 6.886 to 10.858; for m{sub t(D0)}=169GeV, {Delta}k{sub [U(1)]}, from 20.821 to 34.121, {Delta}Q{sub [U(1)]}, from 5.738 to 9.033. These are larger than the standard model radiative correction contributions but an order of magnitude smaller than those predicted by the composite model of Abbott and Farhi.
Sharma, N.K.; Saxena, P.; Singh, S.; Nagawat, A.K.; Sahu, R.S. [Department of Physics, University of Rajasthan, Jaipur 302 004 (India)] [Department of Physics, University of Rajasthan, Jaipur 302 004 (India)
Test Results on Nb3Sn Dipole Magnets
A cosine theta type dipole magnet using Nb{sub 3}Sn conductor have been designed, built and tested. D19H is a two-layer dipole magnet with a Nb{sub 3}Sn inner layer and a NbTi outer layer. Coil-pairs are connected with two of the four Nb{sub 3}Sn splices in a high field region, and compressed by a ring and collet system. It trained well at 4.4K, but poorly at 1.8K. Strain gages revealed that the coil-ends were not loaded well enough for high field operation (after cool-down), so another thermal cycle is planned. The low end-load is believed to be the cause of several mysteries observed during operation. Except for the outer-layer 1.8 K training difficulty, the magnet's operation was encouraging.
Lietzke, A.F.; Benjegerdes, R.; Caspi, S.; Dell'Orco, D.; Harnden, W.; McInturff, A.D.; Morrison, M.; Scanlan, R.M.; Taylor, C.E.; Oort, J.M. van
Magnetic field properties of Fermilab Energy-Saver dipoles
At Fermilab we have operated a production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver/Doubler. At any one time 772 of these dipoles are installed in the accelerator and 62 in beamlines; the remainder are spares. Magnetic field data are now available for most of these dipoles; in this paper we present some of these data which show that we have been able to maintain the necessary consistency in field quality throughout the production process. Specifically we report harmonic field coefficients, showing that the mechanical design permits substantial reduction of the magnitudes of the normal and skew quadrupole harmonic coefficients; field shape profiles; integral field data; and field angle data.
Hanft, R.; Brown, B.C.; Cooper, W.E.; Gross, D.A.; Michelotti, L.; Schmidt, E.E.; Turkot, F.
Magnetic-dipole, quadrupole-dipole and electron-vibration manifestations in chirality
For the first time, quantum chemical and Car-Parinello molecular dynamics simulations of rotation strength dispersion, using restricted Hartree-Fock (RHF) and density functional theory (DFT) approaches, for a biscyanine dye with Schiff base (BDSB) molecule as a model have been performed. We have found that most of the DFT approaches give substantially better agreement with the experimental structural and optical data than the RHF. Contributions of the magnetic-dipole and quadrupole-dipole interactions to the rotation strength spectra were separated. For this reason independent measurements of the rotational strengths (RSs) for the oriented and disordered BDSB molecule were performed. A significant contribution of the anharmonic electron-vibration interaction to the RS was found.
Andraud, C.; Kityk, I. V.; Lemercier, G.; Alexandre, M.; Gruhn, W.
Experimental Proof of Electrically Invisible State of Inductively Loaded Dipole and Proposal of Electrically Invisible Meander-Lines
We examine that an inductively loaded dipole becomes electrical invisible showing that the influence on a nearby antenna's input impedance and on its radiation pattern (scattering) are minimized. We also verify that the direction of the current reverses on the electrically invisible dipole so that the integral of the dipole current becomes zero. By making an inductive load with a
Kyoichi Iigusa; Takuma Sawaya; Makoto Taromaru; Takashi Ohira; Bokuji Komiyama
Strange quark contribution to the neutron electric dipole moment in multi-Higgs doublet models.
The strange quark contribution to the neutron electric dipole moment was studied and compared with other contributions in multi-Higgs doublet models. It was found that the strange quark contribution is significant because the strange quark color dipole mo...
X. G. He H. J. McKeller S. Pakvasa
A multiferroic material to search for the permanent electric dipole moment of the electron.
We describe the first-principles design and subsequent synthesis of a new material with the specific functionalities required for a solid-state-based search for the permanent electric dipole moment of the electron. We show computationally that perovskite-structure europium barium titanate should exhibit the required large and pressure-dependent ferroelectric polarization, local magnetic moments and absence of magnetic ordering at liquid-helium temperature. Subsequent synthesis and characterization of Eu(0.5)Ba(0.5)TiO(3) ceramics confirm the predicted desirable properties. PMID:20639893
Rushchanskii, K Z; Kamba, S; Goian, V; Vanek, P; Savinov, M; Prokleska, J; Nuzhnyy, D; Kn�zek, K; Laufek, F; Eckel, S; Lamoreaux, S K; Sushkov, A O; Lezai?, M; Spaldin, N A
A new experimental limit on the electric dipole moment of the electron
We describe a search for the electric dipole moment d{sub e} of the electron, carried out with {sup 205}Tl atoms in the ground state. The experiment makes use of the separated-oscillating-field magnetic-resonance method, laser state selection, fluorescence detection, and two counter-propagating atomic beams. Very careful attention is paid to systematic effects. The result for the atomic electric dipole moment is d{sub a}=(1.6{plus minus}5.0){times}10{sup {minus}24} e cm. If we assume the theoretical ratio d{sub a}/d{sub e}={minus}600, this yields d{sub e}=({minus}2.7{plus minus}8.3){times}10{sup {minus}27} e cm.
Carlberg, C. (Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)); Abdullah, K.; Commins, E.D. (Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States) Department of Physics, University of California, Berkeley, California 94720 (United States)); Gould, H. (Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)); Ross, S.B. (Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States) Department of Physics, University of California, Berkeley, California, 94720 (United States))
Rashba coupling in three-dimensional wurtzite structure electron gas at electric-dipole spin resonance
Theoretical description of Rashba effects in three-dimensional electron gas at electric-dipole spin resonance conditions is presented in the frame of conductivity tensor formalism. The details due to anisotropy of the effective mass tensor, as well as the Lande factor, are considered. The absorbed power is calculated for arbitrary orientation of the sample with respect to external fields: constant magnetic field and rf electric field. The differences between resonance signals in two- and three-dimensional electron gas are pointed out.
Ungier, W.
This paper describes the design of the coil end for the 50mm aperture SSC collider dipole magnets built at Fermilab. The cable paths are determined from both magnetic and mechanical considerations. The end spacers are designed using the developable surface, grouped end approach, which allows the analysis of strain energy within the conductor groups. Techniques for strain energy minimization are presented and the behavior of individual conductors within a group is analyzed. The relationship between optimization of magnetic and mechanical variables is discussed. Requirements of manufacturing and inspection of coil end parts are outlined. 7 refs.
Brandt, J.; Bartlett, N.; Bossert, R.; Carson, J.; Konc, J.; Lee, G. [Fermi National Accelerator Lab., Batavia, IL (United States); Cook, J. [Argonne National Lab., IL (United States); Caspi, S. [Lawrence Berkeley Lab., CA (United States); Gordon, M.; Nobrega, F. [Superconducting Super Collider Lab., Dallas, TX (United States)
Mechanism of formation of a dipole magnetic field in the central regions of active galaxies
A model of the formation of large-scale magnetic fields of dipole configuration in the central regions (r ? 100 pc) of active galaxies is studied. It is assumed that these regions contain a rapidly rotating, highly ionized gas (? ? 5�10-15 sec, Ne ? 103 cm-3). Ionized matter escapes from the center of the region with a velocity of several hundred km/sec and is entrained by the rotation of the surrounding medium. Biermann's "battery" effect [L. Biermann, Z. Naturforsch., 5a, 65 (1950)] operates under such conditions, and circular electric currents are formed in the medium, which amplify the dipole magnetic fields. During the active phase of a galaxy, about 108 years, the magnetic field strength at the boundary of this region may reach 10-4 10-3 G.
Andreasyan, R. R.
Simple model for tunable vortex pinning by a magnetic dipole
The interaction between one vortex in a thin superconducting film and one magnetic dipole in the presence of a magnetic field applied parallel to the film surfaces is studied theoretically in the London limit. The dipole magnetic moment is assumed to be parallel to the film surfaces, to have constant magnitude, and freedom to rotate. The pinning potential for the vortex is calculated exactly. It is found that, due to the dipole freedom to rotate, the dependence of the pinning potential on the applied field is non-trivial, and allows both the spatial dependence and strength of the pinning potential to be changed by the field. As a consequence, the critical current can be tuned by the applied field. The critical current is obtained numerically as a function of the applied field. Order of magnitude changes in the critical current resulting from changes in the direction and magnitude of the applied field are reported, with discontinuous changes taking place in some cases. Possible application to vortices pinned by arrays of magnetic dots are briefly considered.
Production and Study of High-Beta Plasma Confined by a Superconducting Dipole Magnet
The Levitated Dipole Experiment (LDX)http:\\/\\/psfcwww2.psfc.mit.edu\\/ldx\\/ is a new research facility that is exploring the confinement and stability of plasma created within the dipole field produced by a strong superconducting magnet. Unlike other configurations in which stability depends on curvature and magnetic shear, MHD stability of a dipole derives from plasma compressibility. Theoretically, the dipole magnetic geometry can stabilize a centrally-peaked
Darren Garnier; A. Hansen; M. E. Mauel; E. Ortiz; A. C. Boxer; J. Ellsworth; I. Karim; J. Kesner; S. Mahar; A. Roach
Dipole corrector magnets for the LBNE beam line
The conceptual design of a new dipole corrector magnet has been thoroughly studied. The planned Long-Baseline Neutrino Experiment (LBNE) beam line will require correctors capable of greater range and linearity than existing correctors, so a new design is proposed based on the horizontal trim dipole correctors built for the Main Injector synchrotron at Fermilab. The gap, pole shape, length, and number of conductor turns remain the same. To allow operation over a wider range of excitations without overheating, the conductor size is increased, and to maintain better linearity, the back leg thickness is increased. The magnetic simulation was done using ANSYS to optimize the shape and the size of the yoke. The thermal performance was also modeled and analyzed.
Yu, M.; Velev, G.; Harding, D.; /Fermilab
Experiments to Understand High Temperature Plasma Confinement in Dipole Magnetic Fields
The plans for two new magnetic dipole experiments are discussed in relation to several earlier experiments that have advanced our understanding of confined plasma. For example, early dipole experiments observed St�rmer orbits, the onset of Hamiltonian chaos, and the energy-dependent radial flows induced by drift-resonant fluctuations. The new Levitated Dipole Experiment (LDX) is a device that will enable the first study of the properties of a high-temperature plasma confined by a dipole for many collision times. LDX consists of a high-field, superconducting coil magnetically levitated within a large vacuum vessel. Since field lines pass through the coil, high-temperature plasma having pressure comparable to the confining magnetic pressure ? ~ 1 can be produced and studied. LDX will test recent theories showing unique equilibrium and stability properties of confined plasma with stationary profiles. In the smaller Collisionless Terrella Experiment (CTX), a new array of emissive probes will control the radial electric field in order to systematically investigate both curvature-driven and centrifugally-driven interchange instability and convection.
Mauel, M. E.; Garnier, D. T.; Hansen, A.; Levitt, B.; Maslovsky, D.; Kesner, J.
Candidate molecular ions for an electron electric dipole moment experiment
This paper is a theoretical work in support of a newly proposed experiment [R. Stutz and E. Cornell, Bull. Am. Soc. Phys. 89, 76 (2004)] that promises greater sensitivity to measurements of the electron's electric dipole moment (EDM) based on the trapping of molecular ions. Such an experiment requires the choice of a suitable molecule that is both experimentally feasible and possesses an expectation of a reasonable EDM signal. We find that the molecular ions PtH{sup +} and HfH{sup +} are both suitable candidates in their low-lying {sup 3}{delta} states. In particular, we anticipate that the effective electric fields generated inside these molecules are approximately 73 and -17 GV/cm, respectively. As a byproduct of this discussion, we also explain how to make estimates of the size of the effective electric field acting in a molecule, using commercially available nonrelativistic molecular structure software.
Meyer, Edmund R.; Bohn, John L.; Deskevich, Michael P. [Department of Physics, JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440 (United States); Department of Chemistry and Biochemistry, JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440 (United States)
The electric dipole moment of magnesium deuteride, MgD.
The (0,0) A(2)?-X (2)?(+) band of a cold molecular beam sample of magnesium monodeuteride, MgD, has been recorded field-free and in the presence of a static electric field of up to 11 kV/cm. The lines associated with the lowest rotational levels are detected for the first time. The field-free spectrum was analyzed to produce an improved set of fine structure parameters for the A(2)? (v = 0) state. The observed electric field induced splittings and shifts were analyzed to produce permanent electric dipole moments, [Formula: see text] of 2.567(10)D and 1.31(8)D for A(2)? (v = 0) and X(2)?(+)(v = 0) states, respectively. The recommended value for [Formula: see text](X(2)?(+) (v = 0)) for MgH, based upon the measured value for MgD, is 1.32(8)D. PMID:24929389
Steimle, Timothy C; Zhang, Ruohan; Wang, Hailing
Electric dipole induced by gravity in fat branes
In the fat brane model, also known as the split fermion model, it is assumed that leptons and baryons live in different hypersurfaces of a thick brane in order to explain the proton stability without invoking any symmetry. It turns out that, in the presence of a gravity source M, particles will see different four-dimensional (4D) geometries and hence, from the point of view of 4D-observers, the equivalence principle will be violated. As a consequence, we show that a hydrogen atom in the gravitational field of M will acquire a radial electric dipole. This effect is regulated by the Hamiltonian Hd=??A??r, which is the gravitational analog of the Stark Hamiltonian, where the electric field is replaced by the tidal acceleration A due to the split of fermions in the brane and the atomic reduced mass ? substitutes the electric charge.
Dahia, F.; de Albuquerque Silva, Alex; Romero, C.
We investigate the equilibrium and stability of rigidly rotating quasi-neutral magnetospheres of objects with an aligned magnetic dipole moment, e.g., planetary magnetospheres. We use the Vlasov theory to calculate the equilibria with emphasis on trapped particle populations. Based on a new approach for the description of the trapped particles within the framework of collisionless theory, we calculate self-consistent axisymmetric magnetospheric
T. Neukirch
Low-lying magnetic dipole strength in {sup 163}Dy
We calculated the {ital M}1 strength distribution in {sup 163}Dy within the quasiparticle-phonon nuclear model using the phonon basis for {sup 162}Dy. We found a strong fragmentation of the magnetic dipole strength in {sup 163}Dy which was in qualitative agreement with the experimental data. The calculated fragmentation of the {ital M}1 strength in {sup 163}Dy is much stronger in comparison with that in {sup 162}Dy. {copyright} {ital 1996 The American Physical Society.}
Soloviev, V.G.; Sushkov, A.V.; Shirikova, N.Y. [Joint Institute for Nuclear Research, Bogolubov Laboratory of Theoretical Physics, 141980 Dubna, Moscow region (Russia)] [Joint Institute for Nuclear Research, Bogolubov Laboratory of Theoretical Physics, 141980 Dubna, Moscow region (Russia)
Propagation of slow MHD waves along the dipole magnetic tubes
Variations of plasma pressure in a magnetic flux tube can produce MHD waves evolving into shocks. In the case of low plasma beta, the plasma pressure pulses in the magnetic flux tube generates MHD slow shocks propagating along the tube. In the case of converging magnetic field lines, like in a dipole magnetic field, the cross section of a magnetic flux tube decreases enormously with increasing magnetic field strength. In such a case, the propagation of MHD waves along the magnetic flux tubes is rather different from that in the case of uniform magnetic field. The propagation of MHD slow shocks is studied numerically using an ideal MHD equations in an approximation suitable for a thin magnetic flux tube. In this approximation, the total pressure (sum of magnetic and plasma pressures), is a known function of the distance along the tube. Numerical method used for calculations is based on a conservative finite difference numerical scheme in material coordinates. The result obtained in the numerical study show that the intensity of the slow shock increases very much while the shock is propagating along the narrowing magnetic flux tube towards a region of a strong magnetic field.
Shaidurov, Vladimir A.; Erkaev, Nikolai V.
Parity Violation and Electric Dipole Moments in Atoms and Molecules
We review the current status of the study of parity and time invariance violation in atoms, nuclei and molecules. We focus on parity nonconservation (PNC) in cesium (CS) and three of the most promising areas of research: (i) PNC in a chain of isotopes, (ii) search for nuclear anapole moments, and (iii) search for permanent electric dipole moments (EDMs) of atoms and molecules, which in turn are caused by either an electron EDM or nuclear T, P-odd moments such as a nuclear EDM or nuclear Schiff moment.
Dzuba, V. A.; Flambaum, V. V.
Comparative Anatomy of Dipole Magnets or the Magnet Designer's Coloring Book.
A collection of dipole magnet cross sections is presented together with an indication of how they are related geometrically. The relationships indicated do not necessarily imply the actual path of evolutionary development. Brief consideration is given to ...
R. B. Meuser
Design of a model dipole magnet for the SSC High Energy Booster
A superconducting model dipole magnet has been designed to serve as a vehicle in an R D program to develop a dipole magnet for potential use in the SSC High Energy Booster. The objective has been to use the Brookhaven, National Laboratory (BNL) and Fermi National Accelerator Laboratory (FNAL) 50 mm aperture dipole designs to the maximum possible extent for
N. Hassan; K. Couzens; S. Dwyer; A. Jaisle; R. Jayakumar; S. Krishnamurthy; R. Mihelic; S. Phillips; R. K. Puri; K. Sarna; G. Snitchler; V. Venkatraman
A superconducting model dipole magnet has been designed to serve as a vehicle in an R&D program to develop a dipole magnet for potential use in the SSC High Energy Booster. The objective has been to use the Brookhaven, National Laboratory (BNL) and Fermi National Accelerator Laboratory (FNAL) 50 mm aperture dipole designs to the maximum possible extent for design
Magnetic and Thermal Characteristics of a Model Dipole Magnet for the SIS 300
The synchrotron SIS 300, developed for the Facility for Antiproton and Ion Research (FAIR) project at GSI, will use fast-cycling dipoles with 100 mm inner diameter coils, magnetic field amplitude of 6 T and a ramp rate of 1 T\\/s. This work presents the calculations of the magnetic and thermal characteristics of a 1 m model dipole with optimized 2D
S. Kozub; L. Tkachenko; V. Zubko; E. Floch; J. Kaugerts; G. Moritz; B. Auchmann; S. Russenschuck; D. Tommasini
Micropolar Flow under the Effect of a Magnetic Dipole
In the present paper, we examine the flow of a micropolar fluid under the effect of a line dipole. We present in brief a new general three-dimensional theoretical model that involves the analytical investigation of the partial differential equations, which govern the physical problems of micropolar hydrodynamic flow in magnetic liquids. Then, we study numerically the laminar incompressible flow of a ferromagnetic fluid in a straight square duct, under the effect of a magnetic field. The results show the dependence of the axial velocity and the secondary flow on the main parameters of the problem.
Vafeas, Panayiotis; Papadopoulos, Polycarpos P.; Hatzikonstantinou, Pavlos M.
AC magnetic measurements of the ALS booster dipole engineering model magnet
Ten-Hertz sine wave and two-Hertz sawtooth AC magnetic measurements of the curved Advanced Light Source (ALS) booster dipole engineering model magnet have been accomplished. Long curved coils were utilized to measure the integral transfer function and uniformity. Point coils and a Hall probe were used to measure magnetic induction and its uniformity. The data were logged and processed by a
M. I. Green; E. Hoyer; R. Keller; D. H. Nelson
The Electric Dipole Moment of Iridium Monosilicide, IrSi
The optical spectrum of iridium monosilicide (IrSi) was recently observed using REMPI spectroscopy in the range 17200 to 23850 cm^{-1}. The observation was supported by an ab initio calculation which predicted a X^{2}?_{5/2} state. Here, we report on the analysis of the optical Stark effect for the X^{2}?_{5/2} and [16.0]1.5 (v=6) states. The (6,0)[16.0]1.5 - X^{2}?_{5/2} and the (7,0)[16.0]3.5- X^{2}?_{5/2} bands of IrSi have been recorded using high-resolution laser-induced fluorescence spectroscopy. The observed optical Stark shifts for the ^{193}IrSi and ^{191}IrSi isotopologues were analyzed to produce the electric dipole moments of -0.4139(64)D and 0.7821(63)D for the X^{2}?_{5/2} and [16.0]1.5 (v=6) states, respectively. The negative sign of electric dipole moment of the X^{2}?_{5/2} state is supported by high-level quantum-chemical calculations employing all-electron scalar-relativistic CCSD(T) method augmented with spin-orbit corrections as well as corrections due to full triple excitations. In particular, electron-correlation effects have been shown to be essential in the prediction of the negative sign of the dipole moment. A comparison with other iridium containing molecules will be made. Maria A. Garcia, Carolin Vietz, Fernando Ruip�rez, Michael D. Morse, and Ivan Infante, Kimika Fakultatea, Euskal Herriko. J. Chem. Phys., (submitted)
Le, Anh; Steimle, Timothy C.; Cheng, Lan; Stanton, John F.
Visualizing Special Relativity: The Field of An Electric Dipole Moving at Relativistic Speed
The electromagnetic field is determined for a time-varying electric dipole moving with a constant velocity that is parallel to its moment. Graphics are used to visualize this field in the rest frame of the dipole and in the laboratory frame when the dipole is moving at relativistic speed. Various phenomena from special relativity are clearly�
Smith, Glenn S.
Electric dipole moment signatures of PeV-scale superpartners
A possible supersymmetric interpretation of the new Higgs-like 126 GeV resonance involves a high sfermion mass scale, from tens of TeV to a PeV or above. This scale provides sufficiently large loop corrections to the Higgs mass and can naturally resolve the constraints from flavor-violating observables, even with a generic flavor structure in the sfermion sector. We point out that such high scales could still generate CP-violating electric dipole moments at interesting levels due to the enhancement of left-right sfermion mixing. We illustrate this by saturating the light fermion mass corrections from the sfermion threshold, leaving the gaugino masses unconstrained. In this framework, we find that the current electric dipole moment bounds probe energy scales of 0.1 PeV or higher; this is competitive with the reach of ?K and more sensitive than other hadronic and leptonic flavor observables. We also consider the sensitivity to higher-dimensional supersymmetric operators in this scenario, including those that lead to proton decay.
McKeen, David; Pospelov, Maxim; Ritz, Adam
Electric dipole moments in two-Higgs-doublet models
Electric dipole moments are extremely sensitive probes for additional sources of CP violation in new physics models. Specifically, they have been argued in the past to exclude new CP-violating phases in two-Higgs-doublet models. Since recently models including such phases have been discussed widely, we revisit the available constraints in the presence of mechanisms which are typically invoked to evade flavour-changing neutral currents. To that aim, we start by assessing the necessary calculations on the hadronic, nuclear and atomic/molecular level, deriving expressions with conservative error estimates. Their phenomenological analysis in the context of two-Higgs-doublet models yields strong constraints, in some cases weakened by a cancellation mechanism among contributions from neutral scalars. While the corresponding parameter combinations do not yet have to be unnaturally small, the constraints are likely to preclude large effects in other CP-violating observables. Nevertheless, the generically expected contributions to electric dipole moments in this class of models lie within the projected sensitivity of the next-generation experiments.
Jung, Martin; Pich, Antonio
Magnetic dipole super-resonances and their impact on mechanical forces at optical frequencies.
Artificial magnetism enables various transformative optical phenomena, including negative refraction, Fano resonances, and unconventional nanoantennas, beamshapers, polarization transformers and perfect absorbers, and enriches the collection of electromagnetic field control mechanisms at optical frequencies. We demonstrate that it is possible to excite a magnetic dipole super-resonance at optical frequencies by coating a silicon nanoparticle with a shell impregnated with active material. The resulting response is several orders of magnitude stronger than that generated by bare silicon nanoparticles and is comparable to electric dipole super-resonances excited in spaser-based nanolasers. Furthermore, this configuration enables an exceptional control over the optical forces exerted on the nanoparticle. It expedites huge pushing or pulling actions, as well as a total suppression of the force in both far-field and near-field scenarios. These effects empower advanced paradigms in electromagnetic manipulation and microscopy. PMID:24718235
Liberal, I�igo; Ederra, I�igo; Gonzalo, Ram�n; Ziolkowski, Richard W
The permanent electric dipole moment of vanadium monosulfide
A number of low-J lines of the C 4?-<--X 4?- (0,0) band of a supersonic molecular beam sample of vanadium monosulfide (VS) have been recorded at a resolution of approximately 50 MHz by laser excitation spectroscopy. The electric field induced shift and splitting have been analyzed to give the permanent electric dipole moments ? of the C 4?-(?=0) and X 4?-(?=0) states as 2.38(13) and 5.16(5) D, respectively. An electrostatic model is used to predict ? for VS and VO. A molecular orbital correlation diagram is used to rationalize the trends in experimentally observed ? values of the 3d-monosulfides and 3d-monoxides. A comparison with theoretical predictions is made.
Dipole bending magnets are required to change the horizontal separation of the two beams in the LHC. In Intersection Regions (IR) 1, 2, 5, and 8, the beams are brought into collision for the experiments located there. In IR4, the separation of the beams is increased to accommodate the machine's particle acceleration hardware. As part of the US contribution to the LHC Project, BNL is building the required superconducting magnets. Designs have been developed featuring a single aperture cold mass in a single cryostat, two single aperture cold masses in a single cryostat, and a dual aperture cold mass in a single cryostat. All configurations feature the 80 mm diameter, 10 m long superconducting coil design used in the main bending magnets of the Relativistic Heavy Ion Collider recently completed at Brookhaven. The magnets for the LHC, to be built at Brookhaven, are described and results from the program to build two dual aperture prototypes are presented.
Development of 10 T dipole magnets for the Large Hadron Collider
Development of high field dipole model magnets for future high energy accelerators has been carried out as a part of the cooperative accelerator program between CERN and KEK. A single aperture dipole model magnet was completed and tested. The magnet reached 8.0 T at 4.3 K and 9.87 T at 1.8 K. A twin aperture dipole model magnet with an
Akira Yamamoto; Hiromi Hirabayashi; Hiroshi Yamaoka; Shuma Kawabata; G. Brianti; D. Leroy; R. Perin; L. Walckiers; M. Hirano; S. Ito; I. Inoue; M. Ikeda; M. Kondo
Progress towards an electron electric dipole moment search in Europium-Barium Titanates
We report on recent progress on a search for the electron's electric dipole moment (eEDM) using solid- state Eu0.5Ba0.5TiO3. This material has many desirable properties including ferroelectricity below 200 K and paramagnetism above 1.8 K. When the sample has a non-zero electric polarization, the seven unpaired 4f electrons of the Eu^2+ ions in the lattice feel a large effective electric field of order 10 MV/cm in the direction of the polarization. This causes the electron spins to align with the electric polarization and generate a magnetization, which is measured using DC SQUID magnetometers. We will detail measurements of systematic effects along with recent results toward a measurement of the eEDM.
Eckel, Stephen; Sushkov, Alexander; Lamoreaux, Steven
Electric dipole radiation at VLF in a uniform warm magneto-plasma.
Use of a linear full electromagnetic wave theory to calculate the input impedance of an electric antenna embedded in a uniform, lossless, unbounded warm magnetoplasma, which is assumed to consist of warm electrons and cold ions. In calculating the dipole radiation resistance for the thermal modes and the thermally modified whistler mode the analysis includes the finite temperature only for the electrons. In deriving the formal solution of the warm plasma dipole input impedance a full-wave analysis is used and two antenna orientations are considered, parallel and perpendicular to the static magnetic field. A general dispersion equation governing the modes of propagation is derived and a detailed analysis is made of the propagation characteristics of these modes.
Wang, T. N. C.; Bell, T. F.
Design of 15 mm collars for SSC dipole magnets
Ten 1-m long dipole magnets of the SSC design ''D'' cross section have been constructed and tested. In each model a collar type structure was used to contain and support the coil assembly at assembly and during operation at 4K. The collar structure must provide enough coil compression to minimize training and guarantee the coil cross section dimensions. Three types of collar designs were used. The behavior, measured and predicted, of two types of 15 mm stainless steel collars used on eight of the ten models is examined. The mechanical measurement of the 15 mm stainless steel collars used on eight 1-m dipole models are given. Observed behavior and preliminary design criteria are discussed. In order to better understand observed collar behavior and to evaluate new designs, finite element analysis of the collar designs was undertaken, and results are correlated with measured behavior. The behavior of alternate collar designs is predicted. 3 refs., 19 figs. (LEW)
Peters, C.
A conceptual design is discussed for a fusion rocket propulsion system based on the magnetic dipole configuration. The dipole is found to have features well suited to space applications. Example parameters are presented for a system producing a specific power of 1 kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power toward 10 kW/kg are discussed, as in an approach to implementing the concept through proof-testing on the moon. 21 refs., 14 figs., 2 tabs.
Teller, E.; Glass, A.J.; Fowler, T.K. (Lawrence Livermore National Lab., CA (USA)); Hasegawa, A. (AT and T Bell Labs., Murray Hill, NJ (USA)); Santarius, J.F. (Wisconsin Univ., Madison, WI (USA). Fusion Technology Inst.)
Search for electric dipole moment in 129Xe atom using active nuclear spin maser
An experimental search for an electric dipole moment in the diamagnetic atom 129Xe is in progress through the precision measurement of spin precession frequency using an active nuclear spin maser. A 3He comagnetometer has been incorporated into the active spin maser system in order to cancel out the long-term drifts in the external magnetic field. Also, a double-cell geometry has been adopted in order to suppress the frequency shifts due to interaction with polarized Rb atoms. The first EDM measurement with the 129Xe active spin maser and the 3He comagnetometer has been conducted.
Ichikawa, Y.; Chikamori, M.; Ohtomo, Y.; Hikota, E.; Sakamoto, Y.; Suzuki, T.; Bidinosti, C. P.; Inoue, T.; Furukawa, T.; Yoshimi, A.; Suzuki, K.; Nanao, T.; Miyatake, H.; Tsuchiya, M.; Yoshida, N.; Shirai, H.; Ino, T.; Ueno, H.; Matsuo, Y.; Fukuyama, T.; Asahi, K.
Improved Experimental Limit on the Electric Dipole Moment of the Neutron
An experimental search for an electric dipole moment (EDM) of the neutron has been carried out at the Institut Laue-Langevin, Grenoble. Spurious signals from magnetic-field fluctuations were reduced to insignificance by the use of a cohabiting atomic-mercury magnetometer. Systematic uncertainties, including geometric-phase-induced false EDMs, have been carefully studied. The results may be interpreted as an upper limit on the neutron EDM of vertical bar d{sub n} vertical bar <2.9x10{sup -26}e cm (90% C.L.)
Baker, C. A.; Iaydjiev, P.; Ivanov, S. N. [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Doyle, D. D.; Harris, P. G.; May, D. J. R.; Pendlebury, J. M.; Richardson, J. D.; Shiers, D.; Smith, K. F. [Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH (United Kingdom); Geltenbort, P. [Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France); Green, K.; Grinten, M. G. D. van der [Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH (United Kingdom)
On the use of electric and magnetic data to determine electric sources in a volume conductor
Methods of obtaining detailed information about electrical sources in semi-infinite and spherical volume conductors using\\u000a electric and magnetic surface data are investigated. Surface data produced by various actual sources in the conductors are\\u000a calculated. Using these data, a least-squares error (LSE) solution is then obtained for the dipoles in a multiple dipole assumed\\u000a source and a comparison of the actual
B. Neil Cuffin; Francis Bitter
Progress towards an electric dipole moment measurement in radium-225
The search for a permanent electric dipole moment (EDM) in an atom is a sensitive test of time-reversal symmetry violation. In the nuclear sector, the best limit for T-violation through EDMs is set by measurements of the EDM of the neutron and of the diamagnetic atom Hg-199. Collective and mean field calculations suggest that because of the octupole deformation of its nucleus, Ra-225 (a spin .5ex1-.1em/ -.15em.25ex2 diamagnetic atom with a half life of 15 days) would be two to three orders of magnitude more sensitive to underlying T-violating interactions in the nucleus than Hg-199. Our search for a permanent EDM in Ra-225 involves measuring the nuclear spin precession of polarized Ra-225 atoms held in an optical dipole trap. We will report on recent measurements of atomic properties in Ra as well as progress in the construction of the experiment. This work is supported by DOE, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357.
Sulai, I. A.; Trimble, W.; Ahmad, I.; Bailey, K.; Gould, H. A.; Graner, B.; Greene, J. P.; Holt, R. J.; Korsch, W.; Lu, Z.-T.; Mueller, P.; O'Connor, T. P.
Laser trapping of radium for an electric dipole moment measurement
The best limits on time-reversal violation in the nuclear sector are currently set through electric dipole moment (EDM) searches on the neutron and Hg-199. Recent theoretical calculations predict that atomic EDM measurements of certain octupole-deformed nuclei, e.g., in the radium isotopic chain, are two to three orders of magnitude more sensitive to the underlying time-reversal violation than the one in Hg-199. Ra-225, with nuclear spin 1/2 and a radioactive half-life of 15 days, is a particularly attractive candidate for a tabletop EDM measurement based on a laser-cooling and trapping approach. Towards this end, we have successfully cooled and trapped atoms of Ra-225 and Ra-226 in a magneto-optical trap -- a first for this rare element -- and have identified black-body radiation as a beneficial source of optical repumping. We will present our laser cooling scheme and ongoing measurements of atomic level energies, lifetimes, isotope shifts and hyperfine structure in radium and discuss our progress towards an EDM measurement of Ra-225 based on an optical dipole trap. This work is supported by DOE, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357.
Mueller, P.; Sulai, I. A.; Trimble, W.; Ahmad, I.; Bailey, K.; Bishof, M.; Greene, J. P.; Guest, J. R.; Holt, R. J.; Lu, Z.-T.; O'Connor, T. P.; Gould, H. A.
Analysis of Exploding Plasma Behavior in a Dipole Magnetic Field
Numerical analyses on plasma behaviors in a dipole magnetic field are performed using a three-dimensional (3D) hybrid code. Results are compared with the experimental data and magnetohydrodynamics (MHD) analysis. Dependence of plasma expansion on initial plasma energy and location are discussed by temporal evolutions of plasma position and magnetic field strength. An overall good agreement in the expansion behavior of plasmas among these results is found. The asymmetrical shape of the expanding plasma in the cross-field direction is also noticed, and the reason for this is discussed. For future engineering applications, these results will be useful in designing an optimal configuration of the magnetic thrust chamber for laser fusion rockets, and for studying the effective explosive methods for protecting the earth from collisions by asteroids or comets.
Muranaka, Takanobu; Uchimura, Hideyuki; Nakashima, Hideki; Zakharov, Yuri P.; Nikitin, Sergey A.; Ponomarenko, Arnold G.
RHIC magnet electrical system
The RHIC magnet electrical system consists primarily of the power converters that are used to energize the superconducting magnets in the collider ring, the power distribution system (both room temperature and superconducting) to deliver that power from the converters to the magnets, a detection system to monitor for quenches in the magnets and superconducting cables, and a protection system to remove power from the superconductors if a quench is detected. This system also has major interfaces with the Control System for commands, status monitoring, current setting and analog monitoring of the power supplies, and with Conventional Facilities for power distribution of the mains at and below the 480VAC level.
Bruno, D.; Eng, W.; Feng, P. K.; Ganetis, G.; Lambiase, R. F.; Louie, W.
Field Line Resonances of Hydromagnetic Alfven Waves in Dipole Magnetic Field.
Using the dipole magnetic field model, we have developed the theory of field line resonances of hydromagnetic Alfven waves in general magnetic field geometries. In this model, the Alfven speed thus varies both perpendicular and parallel to the magnetic fi...
L. Chen S. C. Cowley
Gamow-Teller and magnetic dipole transitions for ?, ? and ?
We discuss the effects of the quenching and spreading of the Gamow-Teller (GT) strengths for 0954-3899/24/8/020/img4 and 0954-3899/24/8/020/img5 due to the mixing of the sd-shell components and the halo effects as well as the 0954-3899/24/8/020/img6-hole contributions. The magnetic dipole (M1) transitions between the isobaric analogue state and the GT states for 0954-3899/24/8/020/img4 are studied. It has been found that strong M1 transitions from the IAS occur selectively to several (GT) states.
Suzuki, Toshio
Dipole-exchange spin waves in rectangular magnetic nanowires
Recent Brillouin light scattering experiments on ferromagnetic nanowire arrays together with advances in materials growth techniques have motivated general interest in the spin-wave dynamics of magnetic nanowires. In the first part of this thesis a microscopic theory is developed for the exchange-dominated spin waves in ferromagnetic films with one or more perpendicular truncations. Extensions are then made to long ferromagnetic nanowires with a general cross sectional shape. As examples, this theory is applied to magnetic strips with grooves, ridges or steps, as well as to some wires composed of two different materials in epitaxial contact. In the next several chapters the calculations are generalized to the dipoleexchange spin waves in long antiferromagnetic nanowires with rectangular cross section. The model now includes exchange interactions (along and perpendicular to the wire axis), the long-range dipole-dipole interactions, single-ion anisotropy (which stabilizes the overall antiferromagnetic ordering) and an applied magnetic field. As in bulk materials there are three equilibrium configurations depending of the magnitude of the applied field. These are the low-field antiferromagnetic (AF) phase, the intermediate spin-flop (SF) phase, and the high-field ferromagnetic (F) phase. The spectrum of discrete coupled spin waves is calculated for each phase separately. The transition fields between the different phases are also studied with regards to finite-size effects and effects of the dipolar interactions. The dipolar interactions lead to a general reduction of the transition fields compared with the exchange limit. These calculations show a hysteresis type of effect in the AF ? SF phase transition for the nanowires, while there is a smooth transition between the SF and the F phases. Finally a Green's function method is applied to the antiferromagnetic nanowires in the AF phase. The Green's functions provide more detailed information about the dynamics of the system. Results are deduced for the relative spectral intensities of the spin-wave excitations and for the average square amplitude and ellipticity of precession for the spins in the system. Keywords Spin waves; Magnetic Nanowires; Ferromagnets; Antiferromagnets; Dipole-dipole interactions; Phase transitions; Spin-flop phase.
Nouri, Mohammadrahim
The permanent electric dipole moment of CaOH
The X 2 Sigma(+), A 2Pi, and B 2Sigma(+) states of CaOH are characterized theoretically and experimentally, with a focus on the value of the permanent electric dipole moment (mu). Calculations based on SCF and SDCI studies of CaOH (Bauschlicher et al., 1984 and 1986) give mu values of 0.98, 0.49, and 0.11 D for the X, A, and B states, respectively, in good agreement with experiments in which the pure rotational spectra of these states were not detected. Modified Rittner (1951) and ligand-field models of these states are explored in detail, and the applicability of these results to observational searches for CaOH in circumstellar envelopes is indicated.
Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Steimle, Timothy; Shirley, Jeffrey E.
Search for the electric dipole moment of the ? lepton
We have searched for a CP violation signature arising from an electric dipole moment�(d?) of the ? lepton in the e+e???+?? reaction. Using an optimal observable method and 29.5�fb?1 of data collected with the Belle detector at the KEKB collider at s=10.58�GeV, we find Re(d?)=(1.15�1.70)�10?17�ecm and Im(d?)=(?0.83�0.86)�10?17�ecm and set the 95% confidence level limits ?2.2�10?17
K. Inami; K. Abe; K. Abe; R. Abe; T. Abe; I. Adachi; H. Aihara; M. Akatsu; Y. Asano; T. Aso; V. Aulchenko; T. Aushev; A. M. Bakich; Y. Ban; E. Banas; P. K. Behera; I. Bizjak; A. Bondar; T. E. Browder; P. Chang; Y. Chao; B. G. Cheon; R. Chistov; Y. Choi; L. Y. Dong; S. Eidelman; V. Eiges; Y. Enari; C. Fukunaga; N. Gabyshev; A. Garmash; T. Gershon; B. Golob; C. Hagner; F. Handa; T. Hara; H. Hayashii; M. Hazumi; I. Higuchi; T. Higuchi; Y. Hoshi; W.-S. Hou; H.-C. Huang; T. Igaki; T. Iijima; A. Ishikawa; H. Ishino; R. Itoh; H. Iwasaki; H. K. Jang; J. H. Kang; J. S. Kang; N. Katayama; H. Kawai; Y. Kawakami; N. Kawamura; T. Kawasaki; H. Kichimi; Hyunwoo Kim; J. H. Kim; S. K. Kim; S. Korpar; P. Krokovny; R. Kulasiri; A. Kuzmin; Y.-J. Kwon; J. S. Lange; G. Leder; S. H. Lee; J. Li; D. Liventsev; R.-S. Lu; J. MacNaughton; F. Mandl; T. Matsuishi; S. Matsumoto; T. Matsumoto; W. Mitaroff; H. Miyake; H. Miyake; T. Nagamine; Y. Nagasaka; T. Nakadaira; E. Nakano; M. Nakao; J. W. Nam; S. Nishida; T. Nozaki; S. Ogawa; T. Ohshima; T. Ohshima; S. Okuno; S. L. Olsen; W. Ostrowicz; H. Ozaki; P. Pakhlov; K. S. Park; L. S. Peak; J.-P. Perroud; L. E. Piilonen; K. Rybicki; H. Sagawa; S. Saitoh; Y. Sakai; M. Satapathy; O. Schneider; S. Semenov; K. Senyo; M. E. Sevior; H. Shibuya; B. Shwartz; V. Sidorov; J. B. Singh; N. Soni; S. Stani?; M. Stari?; A. Sugi; A. Sugiyama; K. Sumisawa; T. Sumiyoshi; S. Suzuki; T. Takahashi; F. Takasaki; K. Tamai; N. Tamura; J. Tanaka; M. Tanaka; G. N. Taylor; Y. Teramoto; S. Tokuda; T. Tomura; T. Tsuboyama; S. Uehara; Y. Unno; S. Uno; G. Varner; K. E. Varvell; C. C. Wang; Y. Watanabe; B. D. Yabsley; Y. Yamada; A. Yamaguchi; Y. Yamashita; Y. Yamashita; Z. P. Zhang; V. Zhilich; D. Zontar
K. Inami; K. Abe; K. Abe; R. Abe; T. Abe; I. Adachi; H. Aihara; M. Akatsu; Y. Asano; T. Aso; V. Aulchenko; T. Aushev; A. M. Bakich; Y. Ban; E. Banas; P. K. Behera; I. Bizjak; A. Bondar; T. E. Browder; P. Chang; Y. Chao; B. G. Cheon; R. Chistov; Y. Choi; L. Y. Dong; S. Eidelman; V. Eiges; Y. Enari; C. Fukunaga; N. Gabyshev; A. Garmash; T. Gershon; B. Golob; C. Hagner; F. Handa; T. Hara; H. Hayashii; M. Hazumi; I. Higuchi; T. Higuchi; Y. Hoshi; W.-S. Hou; H.-C. Huang; T. Igaki; T. Iijima; A. Ishikawa; H. Ishino; R. Itoh; H. Iwasaki; H. K. Jang; J. H. Kang; J. S. Kang; N. Katayama; H. Kawai; Y. Kawakami; N. Kawamura; T. Kawasaki; H. Kichimi; Hyunwoo Kim; J. H. Kim; S. K. Kim; S. Korpar; P. Krokovny; R. Kulasiri; A. Kuzmin; Y.-J. Kwon; J. S. Lange; G. Leder; S. H. Lee; J. Li; D. Liventsev; R.-S. Lu; J. MacNaughton; F. Mandl; T. Matsuishi; S. Matsumoto; T. Matsumoto; W. Mitaroff; H. Miyake; H. Miyake; T. Nagamine; Y. Nagasaka; T. Nakadaira; E. Nakano; M. Nakao; J. W. Nam; S. Nishida; T. Nozaki; S. Ogawa; T. Ohshima; T. Ohshima; S. Okuno; S. L. Olsen; W. Ostrowicz; H. Ozaki; P. Pakhlov; K. S. Park; L. S. Peak; J.-P. Perroud; L. E. Piilonen; K. Rybicki; H. Sagawa; S. Saitoh; Y. Sakai; M. Satapathy; O. Schneider; S. Semenov; K. Senyo; M. E. Sevior; H. Shibuya; B. Shwartz; V. Sidorov; J. B. Singh; N. Soni; S. Stani?; M. Stari?; A. Sugi; A. Sugiyama; K. Sumisawa; T. Sumiyoshi; S. Suzuki; T. Takahashi; F. Takasaki; K. Tamai; N. Tamura; J. Tanaka; M. Tanaka; G. N. Taylor; Y. Teramoto; S. Tokuda; T. Tomura; T. Tsuboyama; S. Uehara; Y. Unno; S. Uno; G. Varner; K. E. Varvell; C. C. Wang; Y. Watanabe; B. D. Yabsley; Y. Yamada; A. Yamaguchi; Y. Yamashita; Y. Yamashita; Z. P. Zhang; V. Zhilich; D. Zontar
Improved limit on the muon electric dipole moment
Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muons, as well as the combined result, d{sub {mu}}=(0.0{+-}0.9)x10{sup -19}e cm, are all consistent with zero, we set a new muon EDM limit, |d{sub {mu}}|<1.8x10{sup -19}e cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.
Bennett, G. W.; Brown, H. N.; Bunce, G.; Danby, G. T.; Larsen, R.; Lee, Y. Y.; Meng, W.; Mi, J.; Morse, W. M.; Nikas, D.; Prigl, R.; Semertzidis, Y. K.; Warburton, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States); Bousquet, B.; Cushman, P.; Duong, L.; Giron, S.; Kindem, J.; Kronkvist, I.; Qian, T. [Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455 (United States)] (and others)
Schiff screening of relativistic nucleon electric-dipole moments by electrons
We show, at leading-order in the multipole expansion of the electron-nucleus interaction, that nucleon electric-dipole moments are completely shielded by electrons so that they contribute nothing to atomic electric-dipole moments, even when relativity in the nucleus is taken into account. It is well known that relativistic electron motion, by contrast, leads to dipole moments that are not screened; we discuss the reasons for the difference.
Liu, C.-P.; Engel, J. [T-16, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States)
Nonlinear electrodynamic lensing of electromagnetic waves in a magnetic dipole field
We consider propagation of electromagnetic waves in magnetic dipole and gravitational fields proceeding in accordance with\\u000a the nonlinear vacuum electrodynamics laws. We derive formulas describing the effect of nonlinear electrodynamic lensing of\\u000a electromagnetic waves in the magnetic dipole field. We show that rotation of the magnetic dipole moment about an axis noncoincident\\u000a with this moment leads to a nonlinear electrodynamic
P. A. Vshivtseva; V. I. Denisov; I. V. Krivchenkov
Controlling a nanowire spin-orbit qubit via electric-dipole spin resonance.
A semiconductor nanowire quantum dot with strong spin-orbit coupling (SOC) can be used to achieve a spin-orbit qubit. In contrast to a spin qubit, the spin-orbit qubit can respond to an external ac electric field, an effect called electric-dipole spin resonance. Here we develop a theory that can apply in the strong SOC regime. We find that there is an optimal SOC strength ?(opt)=?2/2, where the Rabi frequency induced by the ac electric field becomes maximal. Also, we show that both the level spacing and the Rabi frequency of the spin-orbit qubit have periodic responses to the direction of the external static magnetic field. These responses can be used to determine the SOC in the nanowire. PMID:24010464
Li, Rui; You, J Q; Sun, C P; Nori, Franco
On field line resonances of hydromagnetic Alfven waves in dipole magnetic field
Using the dipole magnetic field model, developed the theory of field line resonances of hydromagnetic Alfven waves in general magnetic field geometries has been developed. In this model, the Alfven speed thus varies both perpendicular and parallel to the magnetic field. Specifically, it is found that field line resonances do persist in the dipole model. The corresponding singular solutions near
Liu Chen; Steven C. Cowley
Fabrication and test results of a high field, Nb3Sn superconducting racetrack dipole magnet
The LBNL Superconducting Magnet Program is extending accelerator magnet technology to the highest possible fields. A 1 meter long, racetrack dipole magnet, utilizing state-of-the-art Nb3Sn superconductor, has been built and tested. A record dipole filed of 14.7 Tesla has been achieved. Relevant features of the final assembly and test results are discussed
R. Benjegerdes; P. Bish; D. Byford; S. Caspi; D. R. Dietderich; S. A. Gourlay; R. Hafalia; R. Hannaford; H. Higley; A. Jackson; A. Lietzke; N. Liggins; A. D. McInturff; J. O'Neill; E. Palmerston; G. Sabbi; R. M. Scanlan; J. Swanson
On Arnol'd diffusion in a perturbed magnetic dipole field
For certain initial conditions, the motion of charged particles in a magnetic dipole field is well described by the hierarchy of adiabatic invariants: the magnetic moment ?, the longitudinal invariant J, and the magnetic flux ?. Electrostatic waves that break the axisymmetry of the dipole field and resonate with the drift motion can generate large-scale or so-called thick-layer chaos in
Harry P. Warren; A. Bhattacharjee; Michael E. Mauel
Magnetic dipole radiation tailored by substrates: numerical investigation.
Nanoparticles of high refractive index materials can possess strong magnetic polarizabilities and give rise to artificial magnetism in the optical spectral range. While the response of individual dielectric or metal spherical particles can be described analytically via multipole decomposition in the Mie series, the influence of substrates, in many cases present in experimental observations, requires different approaches. Here, the comprehensive numerical studies of the influence of a substrate on the spectral response of high-index dielectric nanoparticles were performed. In particular, glass, perfect electric conductor, gold, and hyperbolic metamaterial substrates were investigated. Optical properties of nanoparticles were characterized via scattering cross-section spectra, electric field profiles, and induced electric and magnetic moments. The presence of substrates was shown to have significant impact on particle's magnetic resonances and resonant scattering cross-sections. Variation of substrate material provides an additional degree of freedom in tailoring optical properties of magnetic multipoles, important in many applications. PMID:24921770
Markovich, D L; Ginzburg, P; Samusev, A K; Belov, P A; Zayats, A V
Electron electric dipole moment and hyperfine interaction constants for ThO
A recently implemented relativistic four-component configuration interaction approach to study P- and T-odd interaction constants in atoms and molecules is employed to determine the electron electric dipole moment effective electric field in the ?=1 first excited state of the ThO molecule. We obtain a value of Eeff=75.2GV/cm with an estimated error bar of 3% and 10% smaller than a previously reported result (Skripnikov et al., 2013). Using the same wavefunction model we obtain an excitation energy of Tv?=1=5410 (cm), in accord with the experimental value within 2%. In addition, we report the implementation of the magnetic hyperfine interaction constant A|| as an expectation value, resulting in A||=-1339 (MHz) for the ?=1 state in ThO. The smaller effective electric field increases the previously determined upper bound (Baron et al., 2014) on the electron electric dipole moment to |de|<9.7�10-29e cm and thus mildly mitigates constraints to possible extensions of the Standard Model of particle physics.
Fleig, Timo; Nayak, Malaya K.
Electric dipole polarizabilities of alkali-metal ions from perturbed relativistic coupled-cluster theory
We use the perturbed relativistic coupled-cluster theory to compute the static electric dipole polarizabilities of the singly ionized alkali-metal atoms, namely, Na+, K+, Rb+, Cs+, and Fr+. The computations use the Dirac-Coulomb-Breit Hamiltonian with the no-virtual-pair approximation and we also estimate the correction to the static electric dipole polarizability arising from the Breit interaction.
Chattopadhyay, S.; Mani, B. K.; Angom, D.
Measurement of the Electric Dipole Polarizabilities of the Homonuclear Alkali Dimer Molecules and Heteronuclear Alkali Dimer Binary Compounds.
The average static electric dipole polarizabilities of homonuclear and heteronuclear alkali dimers were measured by spatial deflection of a molecular beam in an inhomogeneous electric field. The congruent electric and magnetic inhomogeneous fields enables removal of the monomer portion of the beam via the Stern-Gerlach force while the remaining dimer portion is deflected via the electric polarization force. It is assumed that the atomic and molecular constituents possess modified Maxwell-Boltzmann velocity distributions. The Mach number is introduced to describe the sonic properties of the molecular beam. The dimer data analysis consists of a two parameter least squares best fit of the experimental deflection curves to computed ones. The two independent parameters are the dimer polarizability and the Mach number. Beams of NaK and KCs alkali molecules were observed and investigated. Here the deflected curves reflect both the permanent dipole moment and the induced (polarizability) dipole moment. Our experimental observations and numerical analyses show that the presence of the permanent dipole moment shifts the deflection curve of the heteronuclear molecule so its effective polarizability approaches that of the low mass homonuclear dimer. Assuming that the permanent dipole moments are known from theoretical calculations the average static dipole polarizabilities for NaK and KCs were obtained. The measured static dipole polarizabilities in (A^3 ) are: Li_2(948^{circ }K) = 35 +/- 2; Na _2(676^{circ}K) = 39 +/- 3; NaK(612^ {circ}K) = 51 +/- 3; K_2(542^{circ}K) = 77 +/- 5; Rb_2(527 ^{circ}K) = 79 +/- 5; KCs(488^{circ}K) = 89 +/- 5; Cs_2(480 ^{circ}K) = 104 +/- 6.
Tarnovsky, Vladimir
SSC 50 mm dipole magnet cryostat thermal measurement results
A prototype Superconducting Super Collider (SSC) 50 mm dipole magnet cryostat, DCA323, was instrumented at Fermilab and delivered to the SSC Laboratory for installation into the accelerator systems string test facility. In series with other magnets, the instrumented cryostat will be used to quantify and verify cryostat thermal performance with respect to design requirements. Prior to leaving Fermilab, DCA323 was subjected to magnetic testing at the Magnet Test Facility (MTF). This presented an opportunity to obtain preliminary thermal performance data under simulated operating conditions. It should be noted that measurements of overall cryostat thermal performance were not possible during the MTF measurements as the magnet test stands are designed for magnetic rather than thermal testing. They are not designed to limit heat inleak to the ends of the cryostat, which has been shown to have a significant effect on overall measured thermal performance. Nonetheless, these measurements do offer insight into the performance of several of the cryostat components and sub-systems.
Boroski, W.N.; Nicol, T.H.; Ruschman, M.K.; Schoo, C.J.
Interfacial Dipoles and Radiated Energy
Electric dipoles radiate an electromagnetic field into their surroundings. The electric and magnetic fields from a point source or from linear dipoles have components parallel to a spherical surface but also a radial component. In most investigations on radiated fields, only the part of the electric field that is parallel to a spherical surface is taken into account. The argument
Evert C. Slob; Jacob T. Fokkema
6. 4 tesla dipole magnet for the SSC. Revision
A design is presented for a dipole magnet suitable for the proposed SSC facility. Test results are given for model magnets of this design 1 m long and 4.5 m long. Flattened wedge-shaped cables (''keystoned'') are used in a graded, two-layer ''cos theta'' configuration with three wedges to provide sufficient field uniformity and mechanical rigidity. Stainless steel collars 15 mm in radial depth, fastened with rectangular keys, provide structural support, and there is a ''cold'' iron flux return. The outer-layer cable has 30 strands of 0.648 mm diameter NbTi multifilamentary wire with Cu/S.C. = 1.8, and the inner has 23 strands of 0.808 mm diameter wire with Cu/S.C. = 1.3. Performance data are given, including training behavior, winding stresses, collar deformation, and field uniformity. 10 refs., 11 figs.
Taylor, C.E.; Caspi, S.; Gilbert, W.; Hassenzahl, W.; Meuser, R.; Mirk, K.; Peters, C.; Scanlan, R.; Dahl, P.; Cottingham, J.
6. 4 Tesla dipole magnet for the SSC
A design is presented for a dipole magnet suitable for the proposed SSC facility. Test results are given for model magnets of this design 1 m long and 4.5 m long. Flattened wedge-shaped cables (''keystoned'') are used in a graded, two-layer ''cos theta'' configuration with three wedges to provide sufficient field uniformity and mechanical rigidity. Stainless steel collars 15 mm wide, fastened with rectangular keys, provide structural support, and there is a ''cold'' iron flux return. The outer-layer cable has 30 strands of 0.0255 in. dia NbTi multifilamentary wire with Cu/S.C. = 1.8, and the inner has 23 strands of .0318 in. dia wire with Cu/S.C. = 1.3. Performance data is given including training behavior, winding stresses, collar deformation, and field uniformity.
Taylor, C.E.; Caspi, S.; Gilbert, W.; Meuser, R.; Mirk, K.; Peters, C.; Scanlan, R.; Dahl, P.; Cottingham, J.; Hassenzahl, W.
Nonadiabatic behavior of the magnetic moment of a charged particle in a dipole magnetic field
This paper investigates the dynamic behavior of the magnetic moment of a particle confined in a magnetic dipole field in the presence of a low-frequency electrostatic wave. It is shown that there exist two kinds of resonances (the bounce-E x B drift resonance and the wave-drift resonance) by which the adiabaticity of the magnetic moment is broken. The unstable conditions obtained by theoretical considerations showed good agreement with the numerical results.
Murakami, Sadayoshi; Sato, Tetsuya; Hasegawa, Akira
Variations of the dipole magnetic moment of the sun during the solar activity cycle
Observations of the large-scale solar magnetic field (synoptic maps) and measurements of the magnetic field of the Sun as\\u000a a star (the total magnetic field) are used to determine the dipole magnetic moment and direction of the dipole field for three\\u000a successive solar cycles. Both the magnetic moment and its vertical and horizontal components vary regularly during the cycle,\\u000a but
I. M. Livshits; V. N. Obridko
Measurement of the Electron's Electric Dipole Moment in Thorium Monoxide
Some polar diatomic molecules have large effective internal electric fields ({E}_{eff}�10^{11} V/cm that can be used to make measurements of the electron's electric dipole moment (eEDM) with unprecedented sensitivity. By performing precision spectroscopy on the metastable H ^{3}?_{1} state of ThO in a cryogenic buffer gas beam, we have demonstrated a statistical sensitivity to the eEDM of ? d_{e}?1�10^{-28} e\\cdot cm/?{T/{days}}, which is competitive with the current experimental limit, |d_{e}|<1.05�10^{-27}e\\cdot cm. The existence of a non-zero eEDM on this level would be evidence for the existence of interactions that violate parity and time-reversal symmetries that are not included in the Standard Model. Many extensions to the Standard Model (in particular supersymmetric theories) predict the eEDM to be very close to the current experimental limit. We present an overview and discuss the characterization of systematic errors in this experiment. E. R. Meyer and J. L. Bohn, Phys. Rev. A 78, 010502 (2008) J. Hudson, D. Kara, J. Smallman, B. Sauer, M. Tarbutt, E. Hinds, Nature 473 493 (2011) This work is supported by the NSF.
Baron, J.; Demille, D.; Doyle, J.; Gabrielse, G.; Hess, P.; Hutzler, N.; Oleary, B.; Panda, C.; Petrik, E.; Spaun, B.
A Four Vapor Cell Search for the Permanent Electric Dipole Moment of ^199Hg
We are working to improve the limit on the permanent electric dipole moment (EDM) of ^199Hg. The measurement of a finite EDM would reveal a new source of CP violation beyond the standard model. In the experiment, polarized Hg vapor, contained in quartz cells, is placed in parallel magnetic and electric fields, and the spin precession frequency is measured. The present limit(M. V. Romalis, W. C. Griffith, J. P. Jacobs, and E. N. Fortson, Phys. Rev. Lett. 86), 2505 (2001). of |d(^199Hg)|<2.1� 10-28 e cm, was obtained with a two cell configuration, where the cells were placed in a common magnetic field and oppositely directed electric fields. We are presently taking measurements with a four cell version of the experiment. The two additional cells are at zero electric field, and are used to cancel magnetic field gradient noise and to improve our limit on systematic effects due to charging and leakage currents. Changes made to the buffer gas composition of the vapor cells have led to longer and more stable spin coherence times. We have also investigated a complicated light shift effect as a source of noise in the frequency measurements and have taken several steps to reduce this noise. These improvements have increased our statistical sensitivity per unit time by a factor of three. The latest results will be reported.
Griffith, W. C.; Swallows, M. D.; Fortson, E. N.; Romalis, M. V.
Acoustic dipole radiation based conductivity image reconstruction for magnetoacoustic tomography with magnetic induction
Based on the acoustic dipole radiation theory, a tomograhic conductivity image reconstruction algorithm is developed for the magnetoacoustic tomography with magnetic induction (MAT-MI) in a cylindrical measurement configuration. It has been experimentally proved for a tissue-like phantom that not only the configuration but also the inner conductivity distribution can be reconstructed without any borderline stripe. Furthermore, the spatial resolution also can be improved without the limitation of acoustic vibration. The favorable results have provided solid verification for the feasibility of conductivity image reconstruction and suggested the potential applications of MAT-MI in the area of medical electrical impedance imaging.
Sun, Xiaodong; Zhang, Feng; Ma, Qingyu; Tu, Juan; Zhang, Dong
Communication: theoretical study of ThO for the electron electric dipole moment search.
An experiment to search for the electron electric dipole moment (eEDM) on the metastable H(3)?1 state of ThO molecule was proposed and now prepared by the ACME Collaboration [http://www.electronedm.org]. To interpret the experiment in terms of eEDM and dimensionless constant kT, P characterizing the strength of the T,P-odd pseudoscalar-scalar electron-nucleus neutral current interaction, an accurate theoretical study of an effective electric field on electron, Eeff, and a parameter of the T,P-odd pseudoscalar-scalar interaction, WT, P, in ThO is required. We report our results for Eeff (84 GV/cm) and WT, P (116 kHz) together with the hyperfine structure constant, molecule frame dipole moment, and H(3)?1 ? X(1)?(+) transition energy, which can serve as a measure of reliability of the obtained Eeff and WT, P values. Besides, our results include a parity assignment and evaluation of the electric-field dependence for the magnetic g factors in the ?-doublets of H(3)?1. PMID:24329049
Skripnikov, L V; Petrov, A N; Titov, A V
Communication: Theoretical study of ThO for the electron electric dipole moment search
An experiment to search for the electron electric dipole moment (eEDM) on the metastable H3?1 state of ThO molecule was proposed and now prepared by the ACME Collaboration [http://www.electronedm.org]. To interpret the experiment in terms of eEDM and dimensionless constant kT, P characterizing the strength of the T,P-odd pseudoscalar-scalar electron-nucleus neutral current interaction, an accurate theoretical study of an effective electric field on electron, Eeff, and a parameter of the T,P-odd pseudoscalar-scalar interaction, WT, P, in ThO is required. We report our results for Eeff (84 GV/cm) and WT, P (116 kHz) together with the hyperfine structure constant, molecule frame dipole moment, and H3?1 ? X1?+ transition energy, which can serve as a measure of reliability of the obtained Eeff and WT, P values. Besides, our results include a parity assignment and evaluation of the electric-field dependence for the magnetic g factors in the ?-doublets of H3?1.
Skripnikov, L. V.; Petrov, A. N.; Titov, A. V.
Stable orbital motion of magnetic dipole in the field of permanent magnets
In this paper we aim to give a constructive proof of the existence of stable orbital motions of the bodies in the systems which interact only via magnetic forces. To demonstrate this, we give an example of a magnetic system for which we analytically prove G?-stability. We study the dynamics of a small magnetic body, a magnetic dipole, that performs the quasi-orbital motion in the field of two fixed magnetic poles of opposite signs placed at the system�s axis. We use the generalized energy-momentum method to find the conditions of stability of relative equilibria. We also give the realizable physical parameters of the system.
Zub, Stanislav S.
Prospects for an electron electric-dipole-moment search with ferroelectric (Eu,Ba)TiO{sub 3} ceramics
We propose to use ferroelectric (Eu,Ba)TiO{sub 3} ceramics just above their magnetic ordering temperature for a sensitive electron electric-dipole-moment search. We have synthesized a number of such ceramics with various europium concentrations and measured their properties relevant for such a search: permeability, magnetization noise, and ferroelectric hysteresis loops. We also identify and estimate the likely systematics: the magnetoelectric effect, hysteresis-loop heating, and ferroelectric relaxation currents. Our measurements and estimates indicate that a search for the electron electric dipole moment with Eu{sub 0.5}Ba{sub 0.5}TiO{sub 3} could lead to an order of magnitude improvement on the current best limit, if the systematic effects can be controlled.
Sushkov, A. O.; Eckel, S.; Lamoreaux, S. K. [Yale University, Department of Physics, P. O. Box 208120, New Haven, Connecticut 06520-8120 (United States)
Test results from Fermilab 1.5 m model SSC collider dipole magnets.
We will present results from tests of 1.5 m model SSC collider dipole magnets. These R&D magnets are identical to the 15 m full length dipoles currently being assembled at Fermilab in all important aspects except length. Because of their small size they c...
W. Koska R. Bossert J. Carson K. J. Coulter S. Delchamps
Microscopic theory of exchange and dipole-exchange spin waves in magnetic thin films
The aim of this work is to develop a microscopic theory of bulk and surface spin wave modes (or magnons) in thin films of some specific ordered magnetic materials, particularly antiferromagnets. Both exchange and magnetic dipole-dipole interactions are taken into account, depending on the material and the wavevector regime. First we study the dispersion relations of spin waves for situations
Joao Milton Pereira Jr.
Status Report on the Series Production of the Main Superconducting Dipole Magnets for LHC
The LHC accelerator, at present under construction at CERN, Geneva, will make use of 1232 superconducting dipole magnets. The coils are wound with Rutherford type cable based on copper stabilized NbTi superconductors. The LHC machine will be operated at 1.9 K in superfluid helium. The unprecedented mass production of the superconducting dipole magnets, which involves three main contractors in Europe,
F. Savary; M. Bajko; M. Cornelis; P. Fessia; J. Miles; M. Modena; G. de Rijk; L. Rossi; J. Vlogaert
Design and end chamfer simulation of PEFP beam line curved dipole magnets
The design, fabrication and field measurement of 11 DC curved dipole magnets for the PEFP Beam Line have been completed. In this paper, a design method for a complex end chamfer using OPERA-3D is proposed. The conventional method for estimating chamfer shape is extended and applied to a curved dipole magnet by a coordinate transformation. Using the interface with CAD
Ying-Shun Zhu; Mei Yang; Zhuo Zhang; Wan Chen; Bao-Gui Yin; Cai-Tu Shi; Wen Kang
The Superconducting Magnet Division at Brookhaven National Laboratory (BNL) is making and testing 20 insertion region dipoles for the Large Hadron Collider (LHC) at CERN. These 9.45 m-long, 8 cm aperture magnets have the same coil design as the arc dipoles now operating in the Relativistic Heavy Ion Collider (RHIC) at BNL and will be of single and twin aperture
J. F. Muratore; M. Anerella; J. Cozzolino; G. Ganetis; A. Ghosh; R. Gupta; M. Harrison; A. Jain; A. Marone; S. Plate; J. Schmalzle; R. Thomas; P. Wanderer; E. Willen; K. C. Wu
Electric Dipolar Kondo Effect Emerging from a Vibrating Magnetic Ion
When a magnetic ion vibrates in a metal, it inevitably introduces a new channel of hybridization with conduction electrons, and in general, the vibrating ion induces an electric dipole moment. In such a situation, we find that magnetic and nonmagnetic Kondo effects alternatively occur due to the screening of the spin moment and electric dipole moment of the vibrating ion. In particular, the electric dipolar two-channel Kondo effect is found to occur for a weak Coulomb interaction. We also show that a magnetically robust heavy-electron state appears near the fixed point of the electric dipolar two-channel Kondo effect. We believe that the vibrating magnetic ion opens a new door in Kondo physics.
Hotta, Takashi; Ueda, Kazuo
Location and depth estimation of point-dipole and line of dipoles using analytic signals of the magnetic gradient tensor and magnitude of vector components
The magnetic gradient tensor (MGT) provides gradient components of potential fields with mathematical properties which allow processing techniques e.g. analytic signal techniques. With MGT emerging as a new tool for geophysical exploration, the mathematical modelling of gradient tensor fields is necessary for interpretation of magnetic field measurements. The point-dipole and line of dipoles are used to approximate various magnetic objects.
B�lent Oru�
Top quark electric and chromoelectric dipole moments in the general two Higgs doublet model
We study the electric and chromo electric dipole moment of top quark in the\\u000ageneral two Higgs Doublet model (model III). We analyse the dependency of this\\u000aquantity to the new phases coming from the complex Yukawa couplings and masses\\u000aof charged and neutral Higgs bosons. We observe that the electric and chromo\\u000aelecric dipole moments of top quark are
E. O. Iltan
Ramp-rate sensitivity of SSC dipole magnet prototypes
One of the major achievements of the magnet R&D program for the Superconducting Super Collider (SSC) is the fabrication and test of a series of 20 5-cm aperture, 15-m long dipole magnet prototypes. The ramp rate sensitivity of these magnets appears to fall in at least two categories that can be correlated to the manufacturer and production batch of the strands used for the inner-coil cables. The first category, referred to as type-A, is characterized by a strong quench current degradation at high ramp rates, usually accompanied by large distortions of the multipole fields and large energy losses. The second category, referred to as type-B, is characterized by a sudden drop of quench current at low ramp rates, followed by a much milder degradation at larger rates. The multipole fields of the type-B magnets show little ramp-rate sensitivity, and the energy losses are smaller than for the type-A magnets. The behavior of the Type-A magnets can be explained in terms of inter-strand eddy currents arising from low and non-uniform resistances at the crossovers between the strands of the two-layer Rutherford-type cable. Anomalies in the transport-current repartition among the cable strands are suggested as a possible cause for the type-B behavior. The origins of these anomalies have not yet been clearly identified. The SSC project was canceled by decision of the United States Congress on October 21, 1994.
Devred, A.; Ogitsu, T.
Parameter-free description of orbital magnetic dipole strength
The low-lying orbital magnetic dipole strength in even-even nuclei is discussed using a sum-rule approach. It is shown that both the mean excitation energies as well as the summed excitation strengths from the experiment can be described well in heavy nuclei if the moments of inertia and the g factors are substituted by the parameters of the ground-state rotational bands. The influence of the high-lying scissors mode is taken into account explicitly, leading to a successful description of the low-lying mode in heavy deformed nuclei with no free parameters. A quantitative estimate of the gross features of the high-lying mode is deduced. The application of the sum-rule approach to medium-mass nuclei is presented, and the discrepancies with the experimental data are discussed.
Enders, J.; Neumann-Cosel, P. von; Richter, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany); Rangacharyulu, C. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany); Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E4 (Canada)
Progress Toward an Improved Limit on the Permanent Electric Dipole Moment of ^199Hg
We will report on a four vapor cell measurement underway to search for a permanent electric dipole moment (EDM) of ^199Hg. Limits on EDMs of atoms provide strict constraints on supersymmetry and other sources of CP violation beyond the standard model. Currently, the most precise limit on an EDM is given by our previous measurement(M. V. Romalis, W. C. Griffith, J. P. Jacobs, and E. N. Fortson, Phys. Rev. Lett. 86), 2505 (2001). on ^199Hg, which set an upper bound of |d(^199Hg)|<2.1� 10-28 e cm. In the present version of the experiment, a stack of four quartz cells containing polarized Hg vapor is placed in a common magnetic field, and oppositely directed electric fields are applied to the middle two cells. A nonzero EDM would cause a shift in the spin precession frequency between the middle two cells. The additional two cells at zero electric field allow for improved sensitivity due to cancellation of magnetic field gradient noise, and improved limits on possible systematic effects by monitoring magnetic fields caused by leakage and charging currents (see separate abstract, this meeting). First results of the new measurement will be presented.
Griffith, W. C.; Swallows, M. D.; Kogler, L. K.; Fortson, E. N.; Romalis, M. V.
Atomic electric dipole moments: The Schiff theorem and its corrections
Searches for the permanent electric dipole moments (EDMs) of diamagnetic atoms provide powerful probes of CP-violating hadronic and semileptonic interactions. The theoretical interpretation of such experiments, however, requires careful implementation of a well-known theorem by Schiff that implies a vanishing net EDM for an atom built entirely from pointlike, nonrelativistic constituents that interact only electrostatically. Any experimental observation of a nonzero atomic EDM would result from corrections to the pointlike, nonrelativistic, electrostatic assumption. We reformulate Schiff's theorem at the operator level and delineate the electronic and nuclear operators whose atomic matrix elements generate corrections to 'Schiff screening'. We obtain a form for the operator responsible for the leading correction associated with finite nuclear size - the so-called Schiff moment operator - and observe that it differs from the corresponding operator used in previous Schiff moment computations. We show that the more general Schiff moment operator reduces to the previously employed operator only under certain approximations that are not generally justified. We also identify other corrections to Schiff screening that may not be included properly in previous theoretical treatments. We discuss practical considerations for obtaining a complete computation of corrections to Schiff screening in atomic EDM calculations.
Liu, C.-P. [T-16, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Theory Group, Kernfysisch Versneller Instituut, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Ramsey-Musolf, M. J. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Haxton, W. C. [Institute for Nuclear Theory and Department of Physics, University of Washington, Box 351550, Seattle, Washington 98195-1550 (United States); Timmermans, R. G. E.; Dieperink, A. E. L. [Theory Group, Kernfysisch Versneller Instituut, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands)
Model dependence of the {sup 2}H electric dipole moment
Background: Direct measurement of the electric dipole moment (EDM) of the neutron is in the future; measurement of a nuclear EDM may well come first. The deuteron is one nucleus for which exact model calculations are feasible. Purpose: We explore the model dependence of deuteron EDM calculations. Methods: Using a separable potential formulation of the Hamiltonian, we examine the sensitivity of the deuteron EDM to variation in the nucleon-nucleon interaction. We write the EDM as the sum of two terms, the first depending on the target wave function with plane-wave intermediate states, and the second depending on intermediate multiple scattering in the {sup 3}P{sub 1} channel, the latter being sensitive to the off-shell behavior of the {sup 3}P{sub 1} amplitude. Results: We compare the full calculation with the plane-wave approximation result, examine the tensor force contribution to the model results, and explore the effect of short-range repulsion found in realistic, contemporary potential models of the deuteron. Conclusions: Because one-pion exchange dominates the EDM calculation, separable potential model calculations will provide an adequate description of the {sup 2}H EDM until such time as a measurement better than 10% is obtained.
Afnan, I. R.; Gibson, B. F. [School of Chemical and Physical Sciences Flinders University, GPO Box 2100, Adelaide 5001 (Australia); Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Generalized Wannier functions: A comparison of molecular electric dipole polarizabilities
Localized Wannier functions provide an efficient and intuitive means by which to compute dielectric properties from first principles. They are most commonly constructed in a post-processing step, following total-energy minimization. Nonorthogonal generalized Wannier functions (NGWFs) [Skylaris , Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.66.035119 66, 035119 (2002); Skylaris , J. Chem. Phys.JCPSA60021-960610.1063/1.1839852 122, 084119 (2005)] may also be optimized in situ, in the process of solving for the ground-state density. We explore the relationship between NGWFs and orthonormal, maximally localized Wannier functions (MLWFs) [Marzari and Vanderbilt, Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.56.12847 56, 12847 (1997); Souza, Marzari, and Vanderbilt, Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.65.035109 65, 035109 (2001)], demonstrating that NGWFs may be used to compute electric dipole polarizabilities efficiently, with no necessity for post-processing optimization, and with an accuracy comparable to MLWFs.
O'Regan, David D.; Payne, Mike C.; Mostofi, Arash A.
Electric Dipole Moment Measurements with Laser Polarized Radon Isotopes
Electric Dipole Moments (EDM) of atoms and the neutron currently provide stringent limits on new physics that could arise from extensions to the Standard Model such as multiple Higgs, Left-Right Symmtery, and SuperSymmetry. In addition to the need to clarify the origin and mass scale of CP violation, theoretical consideration of the apparent cosmological baryon asymmetry suggests CP violation arising from new physics at the electro-weak scale. Searches for atomic EDMs therefore seek new physics. The heavist atoms are most sensitive to EDMs because they are most polarizable by the CP violating interactions and due to relativistic effects. Noble gas atoms in cells have the experimental advantages of very narrow linewidths and potentiallly large signal, typically providing sub-micro Hz sensitivity to hadronic sources of CP violation. We have resumed the work begun over a decade ago footnote M. Kitano, et al.., PRL 60, 2133 (1988). to study EDM measurements using Rn isotopes. Technical advances in laser optical pumping, cell construction, and systematic effects gained from spin exchange pumped masers, and the promise of Isotope Separators On Line in the US and Canada have motivated a new program of measurements. The interesting possibility that large enhancements of nuclear polarizability^2 could provide 2-3 orders of magnitude greater sensitivity to CP violation than ^199Hg or the neutron provides additional motivation.
Chupp, Timothy
Test results of a single aperture 10 tesla dipole model magnet for the Large Hadron Collider
A single aperture dipole magnet has been developed with a design magnetic field of 10 tesla by using Nb-Ti\\/Cu conductor to be operated at 1.8 K in pressurized super fluid helium, The magnet features double shell coil design by using high keystone Rutherford cable and compact non-magnetic steel collars to be adaptable in split\\/symmetric coil\\/collar design for twin aperture dipoles.
Akira Yamamoto; Takakazu Shintomi; Nobuhiro Kimura; Yoshikuni Doi; Tomiyoshi Haruyama; Norio Higashi; Hiromi Hirabayashi; Hiroshi Kawamata; Seog-Whan Kim; Takamitsu M. Kobayashi; Yasuhiro Makida; Toru Ogitsu; Norihito Ohuchi; Ken-ichi Tanaka; Akio Terashima; Kiyosumi Tsuchiya; Hiroshi Yamaoka; Giorgio Brianti; Daniel Leroy; Romeo Perin; Shoichi Mizumaki; Shuichi Kato
Neptune radio emission in dipole and multipole magnetic fields
We study Neptune's smooth radio emission in two ways: we simulate the observations and we then consider the radio effects of Neptune's magnetic multipoles. A procedure to deduce the characteristics of radio sources observed by the Planetary Radio Astronomy experiment minimizes limiting assumptions and maximizes use of the data, including quantitative measurement of circular polarization. Study of specific sources simulates time variation of intensity and apparent polarization of their integrated emission over an extended time period. The method is applied to Neptune smooth recurrent emission (SRE). Time series are modeled with both broad and beamed emission patterns, and at two frequencies which exhibit different time variation of polarization. These dipole-based results are overturned by consideration of more complex models of Neptune's magnetic field. Any smooth emission from the anticipated auroral radio source is weak and briefly observed. Dominant SRE originates complex fields at midlatitude. Possible SRE source locations overlap that of 'high-latitude' emission (HLE) between +(out) and -(in) quadrupoles. This is the first identification of multipolar magnetic structure with a major source of planetary radio emission.
Sawyer, C. B.; King, N. V.; Romig, J. H.; Warwick, J. W.
Refined representations of the horizontal electric components of the normal field of a high-frequency horizontal electric dipole
Among the components of normal dipole fields useful in high-frequency electric prospecting, the electric components E and E y of the normal field of the horizontal electric dipole are considerably complicated in structure. By checking these values by means of computer mathematics in combination with the development of the classical (dynamical) theory of interference soundings, the above expressions alluded to in geophysical literature were shown to contain considerable errors. The present paper is devoted to this question.
Petrukhin, B. P.
Electric and weak electric dipole form factors for heavy fermions in a general two Higgs doublet model
The electric and weak electric dipole form factors for heavy fermions are calculated in the context of the most general two Higgs doublet model (2HDM). We find that a large top mass can produce a significant enhancement of the electric dipole form factor in the case of the b and c quarks. This effect can be used to distinguish between different 2HDM scenarios.
G�mez Dumm, D.; Gonz�lez-Sprinberg, G. A.
Induced Current on a Long Wire Due to a Vertical Electric Dipole Above Dissipative Ground.
A closed form expression for the induced current along an infinitely long wire due to a distant vertical electric dipole is found. The dipole and the wire are situated above but near a dissipative ground half space. The wire is assumed to be thin but of f...
A. A. Aburwein
The molecular frame electric dipole moment and hyperfine interactions in hafnium fluoride, HfF.
The (1,0) [17.9]2.5-X(2)?(3?2) band of hafnium monofluoride (HfF) has been recorded using high-resolution laser-induced fluorescence spectroscopy both field-free and in the presence of a static electric field. The field-free spectra of (177)HfF, (179)HfF, and (180)HfF were modeled to generate a set of fine and hyperfine parameter for the X(2)?(3?2)(v = 0) and [17.9]2.5 (v = 1) states. The observed optical Stark shifts for the (180)HfF isotopologue were analyzed to produce the molecular frame electric dipole moments of 1.66(1) D and 0.419(7) D for the X(2)?(3?2) and [17.9]2.5 state, respectively. Both the generalized effective core potential and all-electron four component approaches were used in ab initio calculations to predict the properties of ground state HfF including equilibrium distance, dipole moments, quadrupole coupling, and magnetic hyperfine constants. PMID:23556729
Le, Anh; Steimle, Timothy C; Skripnikov, Leonid; Titov, Anatoly V
Streaming of a Plasma through a Magnetic Dipole Field
The two-dimensional motion of a plasma in an inhomogeneous magnetic ; field with circular symmetry and a homogeneous external field under the influence ; of an electric field was studied previously. The influence of space charges was ; taken into account. However, the treatment was generally valid only when no ; forbidden regions for the particles exist. When the inhomogeneity
Erik T. Karlson
The two-dimensional motion of a plasma in an inhomogeneous magnetic field with circular symmetry and a homogeneous external field under the influence of an electric field was studied previously [E. T. Karlson, Phys. Fluids 5, 476 (1962)]. The influence of space charges was taken into account. However, the treatment was generally valid only when no forbidden regions for the particles
Magnetic field measurements of 1. 5 meter model SSC collider dipole magnets at Fermilab
Magnetic field measurements have been performed at Fermilab on 1.5 m magnetic length model dipoles for the Superconducting Supercollider. Harmonic measurements are recorded at room temperature before and after the collared coil is assembled into the yoke and at liquid helium temperature. Measurements are made as a function of longitudinal position and excitation current. High field data are compared with room temperature measurements of both the collared coil and the completed yoked magnet and with the predicted fields for both the body of the magnet and the coil ends.
Lamm, M.J.; Bleadon, M.; Coulter, K.J.; Delchamps, S.; Hanft, R.; Jaffery, T.S.; Kinney, W.; Koska, W.; Ozelis, J.P.; Strait, J.; Wake, M. (Fermi National Accelerator Lab., Batavia, IL (United States)); DiMarco, J. (Superconducting Super Collider Lab., Dallas, TX (United States))
CryoEDM: A cryogenic experiment to measure the neutron electric dipole moment
CryoEDM is an experiment that aims to measure the electric dipole moment (EDM) of the neutron to a precision of 10 -28 e cm. A description of CryoEDM, the apparatus, technologies and commissioning is presented.
van der Grinten, M. G. D.; CryoEDM Collaboration; Balashov, S. N.; Francis, V.; Green, K.; Iaydjiev, P. S.; Ivanov, S. N.; Khazov, A.; Tucker, M. A. H.; Wark, D. L.; Davidson, A.; Hardiman, M.; Harris, P. G.; Katsika, K.; Pendlebury, J. M.; Peeters, S. J. M.; Shiers, D. B.; Smith, P.; Townsley, C.; Wardell, I.; Clarke, C.; Henry, S.; Kraus, H.; McCann, M.; Geltenbort, P.; Yoshiki, Y.
Electromagnetic imaging with an arbitrarily oriented magnetic dipole
We present the theoretical background for the geophysical EM analysis with arbitrarily oriented magnetic dipoles. The first application of such a development is that we would now be able to correct the data when they are not acquired in accordance to the actual interpretation methods. In order to illustrate this case, we study the case of airborne TEM measurements over an inclined ground. This context can be encountered if the measurements are made in mountain area. We show in particular that transient central loop helicopter borne magnetic data should be corrected by a factor proportional to the angle of the slope under the system. In addition, we studied the sensitivity function of a grounded multi-angle frequency domain system. Our development leads to a general Jacobian kernel that could be used for all the induction number and all the position/orientation of both transmitter and receiver in the air layer. Indeed, if one could design a system controlling the angles of Tx and Rx, the present development would allow to interpret such a data set and enhance the ground analysis, especially in order to constrain the 3D anisotropic inverse problem.
Guillemoteau, Julien; Sailhac, Pascal; Behaegel, Mickael
Graded High Field Nb3Sn Dipole Magnets
Dipole magnets with fields beyond 16T will require superconducting coils that are at least 40 mm thick, an applied pres-stress around 150 MPa and a protection scheme for stored energy in the range of 1-2 MJ/m. The coil size will have a direct impact on the overall magnet cost and the stored energy will raise new questions on protection. To reduce coil size and minimize risk, the coil may have to be graded. Grading is achieved by splitting the coil into several layers with current densities that match the short sample field in each layer. Grading, especially at high fields, can be effective; however it will also significantly raise the stress. In this paper we report on the results of a study on the coil size and field relation to that of the stress and stored energy. We then extend the results to graded coils and attempt to address high stress issues and ways to reduce it.
Caspi, S.; Ferracin, P.; Gourlay, S.
Progress Towards a New Measurement of the Electric Dipole Moment of ^199Hg.
We are currently undertaking a four vapor cell search for the permanent electric dipole moment (EDM) of ^199Hg. The existence of a nonzero EDM would imply a source of CP violation beyond the standard model. The present limit on the EDM of ^199 Hg is |dHg| < 2.1 x10-28 ,,, which was established several years ago by our group at the University of Washington. In that experiment, two quartz vapor cells containing polarized Hg vapor were placed in parallel magnetic and anti-parallel electric fields (the use of two cells permitted the removal of common-mode effects), and the spin precession frequency was measured using an optical technique. In our current experiment, two additional cells at zero electric field serve to cancel magnetic gradient noise and to improve limits on systematic effects due to charging and leakage currents. We have recently overcome several systematic issues and begun acquiring data with our upgraded apparatus. To prevent experimenter bias from influencing the data, we have also instituted a blind analysis protocol. The statistical error of the data at the time of this writing was �0.15x10-28 e cm, and we hope to improve the sensitivity by a further factor of two. We will discuss recent progress and our plans to place improved limits on systematic effects.
Swallows, M. D.; Griffith, W. C.; Heckel, B. R.; Fortson, E. N.; Romalis, M. V.
The Search for the Permanent Electric Dipole Moment of ^199Hg
We will report on the search for the permanent electric dipole moment (EDM) of ^199Hg. The discovery of a measurable EDM would imply a new source of CP violation, and the upper bounds on such moments set by current experiments provide useful constraints on supersymmetry and other theories that extend the standard model. The present limit on the EDM of ^199Hg is |d(^199 Hg)| < 2.1 � 10-28 e cm.footnote M. V. Romalis, W. C. Griffith, J. P. Jacobs, and E. N. Fortson, Phys. Rev. Lett. 86, 2505 (2001). In that work, two quartz vapor cells containing polarized Hg vapor were placed in parallel magnetic and anti-parallel electric fields, and the spin precession frequencies were determined using an optical technique. An improved version of that experiment incorporates two additional Hg vapor cells that have no applied electric field. The new cells serve as an additional check on systematic effects, and help cancel noise due to magnetic field gradient fluctuations. We will discuss noise sources and the most important systematics. Our present efforts are focused on understanding the origin of a significant systematic effect that has led to spurious EDM-like signals. Current results will be presented.
Swallows, M. D.; Griffith, W. C.; Kogler, L. K.; Fortson, E. N.; Romalis, M. V.
Permanent dipole magnets for the 8 GeV transfer line at FNAL
The transfer line that will serve to transport 8 GeV protons from the Booster to the new Fermilab Main Injector has been built using permanent magnets. A total of 46 horizontal bend dipoles and 5 vertical bend dipoles were built for this beamline; 67 gradient magnets were also built. The magnets were built using magnetized strontium ferrite bricks. Thermal compensation of these bricks was effected by use of a nickel-iron alloy. The dipole magnets were built with a mean integrated strength of 0.56954 T-m, and an rms spread of 0.06%. The magnets were thermally cycled from 20{degrees}C to 0{degrees}C to condition the ferrite against irreversible thermal losses, and the compensation was measured with a flipcoil. The magnet strength was adjusted by varying the number of bricks installed at the magnet ends. Details of the assembly process and a summary of magnetic measurements are presented here.
Glass, H.D.; Brown, B.C.; Foster, G.W.; Fowler, W.B.; Haggard, J.E. [and others
Mechanical design of the 2D cross-section of the SSC collider dipole magnet
The authors describe the mechanical design of the two-dimensional cross section of the baseline collider dipole magnet for the Superconducting Super Collider. The components described are the collar and yoke laminations and the cold mass shell. The 50-mm-aperture collider dipole magnet uses stainless-steel collars to position the conductors at the locations specified by the magnetic design and to prestress the
J. Strait; J. Kerby; R. Bossert; J. Carson; G. Spigo; J. R. Turner
Assembly and Test of HD2, a 36 mm Bore High Field Dipole Magnet
We report on the fabrication, assembly, and test of the Nb3Sn dipole magnet HD2. The magnet, aimed at demonstrating the application of Nb3Sn superconductor in high field accelerator-type dipoles, features a 36 mm clear bore surrounded by block-type coils with tilted ends. The coil design is optimized to minimize geometric harmonics in the aperture and the magnetic peak field on
Paolo Ferracin; Brad Bingham; Shlomo Caspi; D. W. Cheng; Daniel R. Dietderich; Helene Felice; Arno Godeke; A. R. Hafalia; C. R. Hannaford; J. M. Joseph; A. F. Lietzke; Juan Lizarazo; GianLuca Sabbi; Frederic Trillaud; X. R. Wang
For certain initial conditions, the motion of charged particles in a magnetic dipole field is well described by the hierarchy of adiabatic invariants: the magnetic moment mu, the longitudinal invariant J, and the magnetic flux psi. Electrostatic waves that break the axisymmetry of the dipole field and resonate with the drift motion can generate large-scale or so-called thick-layer chaos in
The neutron electric dipole moment experiment at the FRM-II
The discovery of a neutron electric dipole moment (nEDM) would provide an unambiguous indication of time violation in a fundamental system, and address one of the Sakharov conditions (CP-symmetry violation) necessary to explain the observed matter/antimatter asymmetry in the universe. Current experimental limitations on the nEDM are roughly 6 orders of magnitude above the Standard Model (SM) prediction and so searches for the nEDM provide powerful tests of physics beyond the SM. The nEDM experiment currently under construction at the FRM-II reactor in Munich is seeking to improve this limit up to 2 orders of magnitude. A contextual overview of the relevant physics will be given, and developments in the FRM-II nEDM experiment, including the recent installation of a world-record magnetically shielded room, will be presented.
Marino, Michael
Concept for powering the dipole magnet in a recirculating induction accelerator for heavy ion fusion
In a Recirculating Heavy Ion Fusion Induction Accelerator the largest energy consumption occurs in the bending magnetic fields. Because these fields are pulsed, they cannot be generated by superconducting magnets. The bending magnets will consist of iron core dipoles with multiturn copper conductors. The energy stored in the magnetic field is many tens of megajoules and over 90% of this
L. Reginato; M. Newton; S. Yu
Solar rotating magnetic dipole?. [around axis perpendicular to rotation axis of the sun
A magnetic dipole rotating around an axis perpendicular to the rotation axis of the sun can account for the characteristics of the surface large-scale solar magnetic fields through the solar cycle. The polarity patterns of the interplanetary magnetic field, predictable from this model, agree with the observed interplanetary magnetic sector structure.
Antonucci, E.
R-modes of a neutron star with a magnetic dipole field
We study r-modes of a rotating magnetized neutron star, assuming a magnetic dipole field whose axis is aligned with the axis of rotation. We approach the problem by applying a singular perturbation theory to the oscillations of rotating stars. In this treatment, we divide the star into a thin surface magnetic layer and a non-magnetic core. We integrate linearized ideal
Umin Lee
AC magnetic measurements of the ALS Booster Dipole Engineering Model Magnet
10 Hz sine wave and 2 Hz sawtooth AC magnetic measurements of he curved ALS Booster Dipole Engineering Model Magnet have been accomplished. Long curved coils were utilized to measure the integral transfer function and uniformity. Point coils and a Hall Probe were used to measure magnetic induction and its uniformity. The data were logged and processed by a Tektronix 11401 digital oscilloscope. The dependence of the effective length on the field was determined from the ratio of the integral coil signals to the point coil signals. Quadrupole and sextupole harmonics were derived from the point and integral uniformity measurements. 5 refs., 4 figs., 2 tabs.
Green, M.I.; Keller, R.; Nelson, D.H.; Hoyer, E.
MAGNETIC FIELD MEASUREMENTS OF HD2, A HIgh Nb3Sn DIPOLE MAGNET
The Superconducting Magnet Program at Lawrence Berkeley National Laboratory has designed and tested HD2, a 1 m long Nb{sub 3}Sn accelerator-type dipole based on a simple block-type coil geometry with flared ends. HD2 represents a step toward the development of cost-effective accelerator quality magnets operating in the range of 13-15 T. The design was optimized to minimize geometric harmonics and to address iron saturation and conductor magnetization effects. Field quality was measured during recent cold tests. The measured harmonics are presented and compared to the design values.
Wang, X.; Caspi, S.; Cheng, D. W.; Felice, H.; Ferracin, P.; Hafalia, R. R.; Joseph, J. M.; Lietzke, A. F.; Lizarazo, J.; McInturff, A. D.; Sabbi, G. L.; Sasaki, K.
Electric and magnetic fields
A number of energy momentum anomalies are described that result from the use of Abraham-Lorentz electromagnetic theory. These anomalies have in common the motion of charged bodies or current carrying conductors relative to the observer. The anomalies can be avoided by using the nonflow approach, based on internal energy of the electromagnetic field. The anomalies can also be avoided by using the flow approach, if all contributions to flow work are included. The general objective of this research is a fundamental physical understanding of electric and magnetic fields which, in turn, might promote the development of new concepts in electric space propulsion. The approach taken is to investigate quantum representations of these fields.
Kaufman, H. R.; Robinson, R. S.; Etters, R. D.
Electric and Magnetic Interactions
This book offers a myriad of lessons, experiments, and demonstrations in all topics in the field of electricity and magnetism. From charge interactions to electromagnetic radiation and induction, it covers the material of a second semester calculus-based introductory physics course. This book is the second of two in the Matter & Interactions series. The Matter & Interactions series emphasizes that there are only a few fundamental principles that underlie the behavior of matter, and that it is possible to construct models that can explain and predict a wide variety of physical phenomena using these principles.
Chabay, Ruth; Sherwood, Bruce
Finite-element structural analysis of the 10 m long dipole prototype magnet for the LHC
In the framework of the R&D program for the LHC (Large Hadron Collider) superconducting magnets, a series of dipole prototypes, manufactured by European firms, will be placed in a test cell of the LHC machine to be tested in the second part of 1992. The design of the cross-section of the full length dipole prototype is a natural evolution from
M. Bona; D. Perini
Electric dipole moments and polarizability in the quark-diquark model of the neutron
For a bound state internal wave function respecting parity symmetry, it can be rigorously argued that the mean electric dipole moment must be strictly zero. Thus, both the neutron, viewed as a bound state of three quarks, and the water molecule, viewed as a bound state of ten electrons, two protons, and an oxygen nucleus, have zero mean electric dipole moments. Yet, the water molecules are said to have a nonzero dipole moment strength d=e{Lambda} with {Lambda}{sub H{sub 2O{approx_equal}}}0.385 A. The neutron may also be said to have an electric dipole moment strength with {Lambda}{sub neutron{approx_equal}}0.612 fm. The neutron analysis can be made experimentally consistent, if one employs a quark-diquark model of neutron structure.
Srivastava, Y. N. [Physics Department, University of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Physics Department, Northeastern University, Boston, Massachusetts 02115 (United States); INFN, Sezione di Perugia, Via A. Pascoli, 06123 Perugia (Italy); Widom, A.; Swain, J. [Physics Department, Northeastern University, Boston, Massachusetts 02115 (United States); Panella, O. [INFN, Sezione di Perugia, Via A. Pascoli, 06123 Perugia (Italy)
Discrepancy in the near-solute electric dipole moment calculated from the electric field.
The electric dipole moment p(r) was computed as the integral of the permanent dipole moment of the solvent molecule ?(r) weighted by the orientational probability distribution ?(r;O) over all orientations, where O is the orientation of the solvent molecule at r. The relationship between ?(r;O) and the potential of the mean torque was derived; p(r) is proportional to the electric field E(r) under the following assumptions: (1) the van der Waals (vdW) interaction is independent of the orientation of the solvent molecule at r; (2) the solvent molecule and its electrical effect are modeled as a point dipole moment; (3) the solvent molecule at r is in a region far from the solute; and (4) ?E(r) ? k(B) T, where k(B) is Boltzmann's constant and T is absolute temperature. The errors caused by calculating near-solute ?(r) and p(r) from E(r) are unclear. The results show that ?(r) is inconsistent with the value calculated from E(r) for water molecules in the first and second shells of solute with charge state Q = �1 e, and a large variation in solvent molecular polarizability ?(mol) (r), which appeared in the first valley of 4?r(2) E(r) for |Q| < 1 e. Nonetheless, p(r) is consistent with the values calculated from E(r) for |Q| ? 1 e. The implication is that the assumptions for calculating p(r) can be ignored in the calculation of the solvation free energy of biomolecules, as they pertain to protein folding and protein-protein/ligand interactions. PMID:21717477
Yang, Pei-Kun
Stochastic dynamics of electric dipole in external electric fields: A perturbed nonlinear pendulum approach
The motion of a dipole in external electric fields is considered in the framework of nonlinear pendulum dynamics. A stochastic layer is formed near the separatrix of the dipole pendulum in a restoring static electric field under the periodic perturbation by plane-polarized electric fields. The width of the stochastic layer depends on the direction of the forcing field variation, and this width can be evaluated as a function of perturbation frequency, amplitude, and duration. A numerical simulation of the approximate stochastic layer width of a perturbed pendulum yields a multi-peak frequency spectrum. It is described well enough at high perturbation amplitudes by an analytical estimation based on the separatrix map with an introduced expression of the most effective perturbation phase. The difference in the fractal dimensions of the phase spaces calculated geometrically and using the time-delay reconstruction is attributed to the predominant development of periodic and chaotic orbits, respectively. The correlation of the stochastic layer width with the phase space fractal dimensions is discussed.
Kapranov, Sergey V.; Kouzaev, Guennadi A.
Direct detection of light anapole and magnetic dipole DM
We present comparisons of direct detection data for ``light WIMPs'' with an anapole moment interaction (ADM) and a magnetic dipole moment interaction (MDM), both assuming the Standard Halo Model (SHM) for the dark halo of our galaxy and in a halo-independent manner. In the SHM analysis we find that a combination of the 90% CL LUX and CDMSlite limits or the new 90% CL SuperCDMS limit by itself exclude the parameter space regions allowed by DAMA, CoGeNT and CDMS-II-Si data for both ADM and MDM. In our halo-independent analysis the new LUX bound excludes the same potential signal regions as the previous XENON100 bound. Much of the remaining signal regions is now excluded by SuperCDMS, while the CDMSlite limit is much above them. The situation is of strong tension between the positive and negative search results both for ADM and MDM. We also clarify the confusion in the literature about the ADM scattering cross section.
Del Nobile, Eugenio; Gelmini, Graciela B.; Gondolo, Paolo; Huh, Ji-Haeng
Magnetic designs of 2-in-1 Nb3Sn dipole magnets for VLHC
The paper presents the results of a conceptual design study of double aperture Nb3Sn dipole magnets for VLHC based on the cos-theta and common coil geometry with cold and warm iron yoke. The study included an optimization of the iron yoke geometry to achieve the maximum transfer function, small fringe fields and low-order field harmonics as well as an optimization
Vadim V. Kashikhin; Alexander V. Zlobin
AC magnetic measurements of the ALS Booster Synchrotron Dipole Magnet engineering model
We made a minimal set of AC magnetic measurements of the engineering model of the ALS Booster Dipole Magnet as part of the process of qualifying its design for production. Magnetic induction integrals over paths approximating electron-beam trajectories were measured with long curved coils connected to an electronic integrator. Magnetic induction was measured with point coils and an integrator and independently with a Hall-effect Gaussmeter. These quantities, and magnet current, were displayed on a commercial digital storage oscilloscope as parametric functions of time. The displayed waveforms were stored, processed and redisplayed as representations of selected magnet parameters. A waveform representing the magnet's effective-length was created by dividing the integral waveform by the magnetic induction waveform. Waveforms of the transfer functions were produced by dividing both the integral waveform and the magnetic induction waveform by the current waveform. Pairs of matched coils, connected in series opposition, provided differential measurements of field uniformity. Quadrupole and sextupole coefficients were derived from the uniformity data. These magnet parameters were measured at 2 and 10 Hz frequencies. Together with measurements of the magnetic field at selected dc levels, the ac measurements demonstrated that the magnet design met specifications and qualified it for production. 7 refs., 7 figs., 3 tabs.
Green, M.I.; Hoyer, E.; Keller, R.; Nelson, D.H.
Tests of Fermilab built 40 mm aperture full length SSC dipole magnets.
Several 40 mm aperture, 17 m long dipoles have been built by Fermilab as developmental prototypes for the Superconducting Super Collider. These magnets differ from those manufactured at Brookhaven National Laboratory in that they have an external inner-ou...
W. Koska M. Bleadon R. Bossert J. Carson S. Delchamps
Heat leak testing of a superconducting RHIC dipole magnet at Brookhaven National Laboratory
Brookhaven National Laboratory is currently performing heat load tests on a superconducting dipole magnet. The magnet is a prototype of the 360, 8 cm bore, arc dipole magnets that will be used in the Relativistic Heavy Ion Collider (RMC). An accurate measurement of the heat load is needed to eliminate cumulative errors when determining the REUC cryogenic system load requirements. The test setup consists of a dipole positioned between two quadrupoles in a common vacuum tank and heat shield. Piping and instrumentation are arranged to facilitate measurement of the heat load on the primary 4.6 K magnet load and the secondary 55 K heat shield load. Initial results suggest that the primary heat load is well below design allowances. The secondary load was found to be higher than estimated, but remained close to the budgeted amount. Overall, the dipole performed to specifications.
DeLalio, J.T.; Brown, D.P.; Sondericker, J.H.
Measurements of the Persistent Current Decay and Snapback Effect in Tevatron Dipole Magnets.
A systematic study of the persistent current decay and snapback effect in the fields of Tevatron accelerator dipoles was performed at the Fermilab Magnet Test Facility (MTF). The decay and snapback were measured under a range of conditions including varia...
G. V. Velev J. DiMarco M. Lamm P. Bauer P. Schlabach R. Hanft
Heat transfer augmentation using a magnetic fluid under the influence of a line dipole
Ferrofluids have promising potential for heat transfer applications, since advective transport in a ferrofluid can be readily controlled by using an external magnetic field. However, unlike conventional free or forced convection, ferrohydrodynamic convection is not yet well characterized. A full understanding of the relationship between an imposed magnetic field, the resulting ferrofluid flow, and the temperature distribution is a prerequisite for the proper design and implementation of applications involving thermomagnetic convection. The literature variously assumes constant magnetic fields, does not completely represent the variation in the imposed field, or its descriptions are inaccurate, since the fields do not comply with the Maxwell's equations of electromagnetism. We address this by simulating two-dimensional forced convection heat transfer in a channel with a ferrofluid that is under the influence of a two-dimensional magnetic field created by a line-source dipole. Our objective is to characterize the heat transfer augmentation due to the thermomagnetic convection and correlate it with the properties of the imposed magnetic field. We determine that magnetic effects on the corresponding flow are localized. The local asymmetry in the thermal boundary layer about the line dipole and the resulting spatial nonuniformity of the fluid susceptibility causes colder fluid to move closer to the line dipole. Thus, the magnetic field induces the production of a local vortex near the cold wall. This alters the advection energy transport, changes the temperature distribution in the flow and enhances the heat transfer. The addition of dipoles is beneficial for heat transfer, since they create additional recirculation zones. Heat transfer is also affected while the spacing between the two dipoles is varied. Thus, an enhancement in the overall heat transfer depends on the net magnetizing current as well as the relative placement of the dipoles. For hydrodynamically similar cases, the heat transfer enhancement produced by a magnetic field can be predicted if information regarding the magnetic moment of the field-inducing magnet and the distribution of the representative line dipoles are known.
Ganguly, Ranjan; Sen, Swarnendu; Puri, Ishwar K.
Superconducting magnets at Brookhaven National Laboratory. AGS high energy unseparated beam line dipoles and ISABELLE ring magnet prototypes
In the last two years the ISABELLE Division of Brookhaven National Laboratory has constructed various superconducting dipoles in their search for the optimum magnet on which to base the storage ring design. Data taken for two of the larger size systems that have been completed to date are reported. The first system is composed of four large superconducting dipoles used
Design study of a superconducting dipole model magnet for the Large Hadron Collider
A design study of a high-field superconducting dipole magnet for the LHC (Large Hadron Collider) project has been carried out in cooperation between CERN and KEK. The objective is to develop a 1-m twin-aperture dipole model magnet based on double shell coil design with a fully symmetric split collaring structure. Development of superconducting cable with high keystone angle is a
Hiromi Hirabayashi; Akira Yamamoto; Shuma Kawabata; Giorgio Brianti; Daniel Leroy; Romeo Perin
Ejection of magnetic-field-sensitive atoms from an optical dipole trap
Rubidium atoms prepared by evaporative cooling in an optical dipole trap are used in Stern-Gerlach type experiments. The analysis of the magnetic state distribution in the trap and during free fall demonstrates the possibility of ejecting all atoms with mF!=0 from the optical dipole trap. This is achieved by applying an appropriately located inhomogeneous magnetic field. We investigate the dynamics
C. K�fer; R. Bourouis; J. Eurisch; A. Tripathi; H. Helm
Performance of the LHC final prototype and first pre-series superconducting dipole magnets
Within the LHC cryo-dipole program, six full-scale superconducting prototypes of final design were built in collaboration between Industry and CERN, followed by launching the manufacture of pre-series magnets. Five prototypes and the first of the pre-series magnets were tested at CERN. This paper reviews the main features and the performance of the cryo-dipoles tested at 4.2 K and 1.8 K.
L. Bottura; G. D'Angelo; M. Gateau; P. Legrand; M. Modena; K. Naoui; D. Perini; P. Pugnat; S. Sanfilippo; F. Savary; Walter Scandale; A. Siemko; P. Sievers; G. Spigo; J. Vlogaert; C. Wyss
Interaction of a weak gravitational wave with a rotating magnetic dipole field
The interaction of a weak gravitational wave of specified frequency with a magnetic-dipole field rotating at a frequency much less than the gravitational-wave frequency is analyzed. The gravitational-wave source is assumed to be situated at the center of the magnetic dipole. It is shown that the interaction results in the production of an electromagnetic wave with the same frequency as
V. I. Denisov
A Computationally Compact Representation of Magnetic-Apex and Quasi-Dipole Coordinates with Smooth Base Vectors
Many structural and dynamical features of the ionized and neutral upper atmosphere are strongly organized by the geomagnetic field, and several magnetic coordinate systems have been developed to exploit this organization. Modified Apex coordinates are appropriate for calculations involving electric fields and magnetic-field-aligned currents; Quasi-Dipole coordinates are appropriate for calculations involving horizontally stratified phenomena like height-integrated currents, electron densities, and thermospheric winds. Both of these coordinate systems are based on the International Geomagnetic Reference Field (IGRF), but their calculation requires computationally expensive tracing of magnetic field lines to their apexes. Interpolation on a precomputed grid provides faster coordinate conversions, but requires the overhead of a sufficiently fine grid, as well as finite differencing to obtain coordinate base vectors. To address these difficulties, we developed a compact, smooth, and robust representation of the transformation from geodetic to Quasi-Dipole, Apex, and Modified Apex coordinates, by fitting the Quasi-Dipole coordinates to spherical harmonics in geodetic longitude and latitude, and to a polynomial of a reduced height parameter. With this representation, Quasi-Dipole and Modified Apex base vectors may be calculated directly from the expansion coefficients. For an expansion truncated at order 6, the fitted coordinates deviate from the actual coordinates by a maximum of 0.4�, and typically by 0.1�. Compared to interpolation on a pre-computed grid, the spherical harmonic representation is much more compact and provides smooth base vectors; the computational speed is about the same. In this presentation, we review the characteristics of several magnetic coordinate systems, describe our compact representation of Quasi-Dipole and Modified Apex coordinates, and demonstrate its application to ionospheric modeling and data analysis.
Emmert, J. T.; Richmond, A. D.; Drob, D. P.
Spin exchange and magnetic dipole-dipole interactions leading to the magnetic superstructures of MAs2O6 (M = Mn, Co, Ni).
The three isostructural magnetic oxides MAs2O6 (M = Mn, Co, Ni) containing high-spin M(2+) ions undergo a long-range antiferromagnetic ordering below 30 K, but their ordered magnetic structures are not identical. While CoAs2O6 and NiAs2O6 adopt the commensurate superstructure of q1 = (0, 0, 1/2), MnAs2O6 has the incommensurate superstructure of q2 = (0.055, 0.389, 0.136). The cause for this difference was examined by calculating their spin exchange and magnetic dipole-dipole interaction energies. In CoAs2O6 and NiAs2O6, the strongest M-O���O-M spin exchange, J1, dominates over other exchanges, hence leading to the q1 superstructure. For MnAs2O6, the spin exchanges are not a deciding factor leading to its magnetic superstructure, being all weak and comparable in strengths, but the magnetic dipole-dipole interactions are. PMID:24601528
Koo, Hyun-Joo; Whangbo, Myung-Hwan
Magnetic design of the Fermilab 11 T Nb3Sn short dipole model
High field accelerator magnets for a future Very Large Hadron Collider are being developed at Fermilab in collaboration with LBNL and KEK. The goal of this work is to elaborate a cost-effective Nb3 Sn dipole magnet design and technology which provide the nominal field of 11 T. This paper presents a description of the magnetic design of the first short
G. Ambrosio; N. Andreev; S. Caspi; K. Chow; V. V. Kashikhin; I. Terechkine; M. Wake; S. Yadav; R. Yamada; A. V. Zlobin
Axisymmetric p-mode pulsations of stars with dipole magnetic fields
The effect of a dipole magnetic field on adiabatic axisymmetric non-radial p-mode pulsations is studied numerically. The angular dependence of pulsation, which cannot be represented by a single spherical harmonic in the presence of a magnetic field, is expanded into a series of spherical harmonics with different degrees l. The presence of a magnetic field not only shifts the pulsation
Hideyuki Saio; Alfred Gautschy
Polarizabilities And Electric Dipole Moments In The Excited States Of Some Cycloaducts
The polarizabilities and the dipole moments in the excited electronic states of some spectrally active molecules are estimated from the solvent influence on the electronic spectra. The Abe model and the model of dispersive interactions was used in this purpose. The values of the polarizabilities and electric dipole moments in the ground state were computed by using the software packages HyperChem and ChemOffice Ultra2005. Some cycloaducts of cycloimmonium ylids were used as spectrally active molecules.
Dimitriu, Mihaela; Dimitriu, Dan; Dorohoi, Dana-Ortansa
Ultrafast coherent control of giant oscillating molecular dipoles in the presence of static electric fields
We propose a scheme to generate electric dipole moments in homonuclear molecular cations by creating, with an ultrashort pump pulse, a quantum superposition of vibrational states on electronic states strongly perturbed by very strong static electric fields. By field-induced molecular stabilization, the dipoles can reach values as large as 50 Debyes and oscillate on a time-scale comparable to that of the slow vibrational motion. We show that both the electric field and the pump pulse parameters can be used to control the amplitude and period of the oscillation, while preventing the molecule from ionizing or dissociating.
Chang, Bo Y.; Shin, Seokmin; Palacios, Alicia; Mart�n, Fernando; Sola, Ignacio R.
Effects of MHD slow shocks propagating along magnetic flux tubes in a dipole magnetic field
Variations of the plasma pressure in a magnetic flux tube can produce MHD waves evolving into shocks. In the case of a low plasma beta, plasma pressure pulses in the magnetic flux tube generate MHD slow shocks propagating along the tube. For converging magnetic field lines, such as in a dipole magnetic field, the cross section of the magnetic flux tube decreases enormously with increasing magnetic field strength. In such a case, the propagation of MHD waves along magnetic flux tubes is rather different from that in the case of uniform magnetic fields. In this paper, the propagation of MHD slow shocks is studied numerically using the ideal MHD equations in an approximation suitable for a thin magnetic flux tube with a low plasma beta. The results obtained in the numerical study show that the jumps in the plasma parameters at the MHD slow shock increase greatly while the shock is propagating in the narrowing magnetic flux tube. The results are applied to the case of the interaction between Jupiter and its satellite Io, the latter being considered as a source of plasma pressure pulses.
Erkaev, N. V.; Shaidurov, V. A.; Semenov, V. S.; Biernat, H. K.
Fabrication and test results of a Nb3Sn superconducting racetrack dipole magnet
A �proof-of-principle� Nb3Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets
K. Chow; D. R. Dietderich; S. A. Gourlay; R. Gupta; W. Harnden; A. F. Lietzke; A. D. McInturff; G. A. Millos; L. Morrison; R. M. Scanlan
A summary of SSC dipole magnet field quality measurements
This paper reports results of field quality measurements of the initial 15 m-long, 50 mm-aperture SSC Collider dipoles tested at Brookhaven National Laboratory and Fermi National Laboratory. These data include multipole coefficients and the dipole angle at room temperature and 4.35 K, 4.35 K integral field measurements, and time-dependent effects. Systematic uncertainties are also discussed.
P. Wanderer; M. Anerella; J. Cottingham; G. Ganetis; M. Garber; A. Ghosh; A. Greene; R. Gupta; A. Jain; S. Kahn; E. Kelly; G. Morgan; J. Muratore; A. Prodell; M. Rehak; E. P. Rohrer; W. Sampson; R. Shutt; R. Thomas; P. Thompson; E. Willen; A. Devred; T. Bush; R. Coombes; J. DiMarco; C. Goodzeit; J. Kuzminski; W. Nah; T. Ogitsu; M. Puglisi; P. Radusewicz; P. Sanger; R. Schermer; J. Tompkins; J. Turner; Y. Yu; Y. Zhao; H. Zheng; M. Bleadon; R. Bossert; J. Carson; S. Delchamps; S. Gourlay; R. Hanft; W. Koska; M. Kuchnir; M. Lamm; P. Mantsch; P. O. Mazur; D. Orris; T. Peterson; J. Strait; M. Wake; J. Royet; R. Scanlan; C. Taylor
Magnetohydrodynamic Simulations of Hypersonic Flow over a Cylinder Using Axial- and Transverse-Oriented Magnetic Dipoles
Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (?1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source terms such as Lorentz force and Joule dissipation. The results demonstrate the ability of the magnetic field to affect the flowfield around the cylinder, which results in an increase in shock stand-off distance and reduction in overall temperature. Also, it is observed that there is a noticeable decrease in drag with the addition of the magnetic field.
Guarendi, Andrew N.; Chandy, Abhilash J.
Magnetohydrodynamic simulations of hypersonic flow over a cylinder using axial- and transverse-oriented magnetic dipoles.
Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (<1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source terms such as Lorentz force and Joule dissipation. The results demonstrate the ability of the magnetic field to affect the flowfield around the cylinder, which results in an increase in shock stand-off distance and reduction in overall temperature. Also, it is observed that there is a noticeable decrease in drag with the addition of the magnetic field. PMID:24307870
Guarendi, Andrew N; Chandy, Abhilash J
Electric and Magnetic Field Sensor for Simultaneous Electromagnetic Near-Field Measurements--Theory.
The paper describes the theory of a single sensor to perform simultaneous electric and magnetic near-field measurements. The theory indicates that it is possible to obtain the magnetic-loop and electric-dipole currents using a loop terminated with identic...
M. Kanda
Microscopic description of the low lying and high lying electric dipole strength in stable Ca isotopes
The properties of the low lying and high lying electric dipole strength in the stable 40Ca, 44Ca and 48Ca isotopes have been calculated within the Extended Theory of Finite Fermi Systems (ETFFS). This approach is based on the random phase approximation (RPA) and includes the single particle continuum as well as the coupling to low lying collective states which are considered in a consistent microscopic way. For 44Ca we also include pairing correlations. We obtain good agreement with the existing experimental data for the gross properties of the low lying and high lying strength. It is demonstrated that the recently measured A-dependence of the electric dipole strength below 10 MeV is well understood in our model: due to the phonon coupling some of the strength in 48Ca is simply shifted beyond 10 MeV. The predicted fragmentation of the strength can be investigated in (e,e) and (?,?) experiments. The isovector dipole strength below 10 MeV is small in all Ca isotopes. Surprisingly, the proton and neutron transition densities of these low lying electric dipole states are in phase, which indicate isoscalar structure. We conclude that for the detailed understanding of the structure of excited nuclei e.g. the low lying and high lying electric dipole strength an approach like the present one is absolutely necessary.
Tertychny, G.; Tselyaev, V.; Kamerdzhiev, S.; Gr�mmer, F.; Krewald, S.; Speth, J.; Avdeenkov, A.; Litvinova, E.
On the resource evaluation of marine gas hydrate deposits using sea-floor transient electric dipole-dipole methods
Methane hydrates are solid, nonstoichiometric mixtures of water and the gas methane. The depth extent and stability of the hydrate zone is governed by the phase diagram for mixtures of methane and hydrate and determined by ambient pressures and temperatures. The base of the hydrate zone is a phase boundary between solid hydrate and free gas and water. It stands out on seismic sections as a bright reflection. The diffuse upper boundary is not as well marked so that the total mass of hydrate is not determined easily by seismic alone. The addition of electrical data, collected with a seafloor transient electric dipole-dipole system, can aid in the evaluation of the resource. Two exploration scenarios are investigated through numerical modeling. In the first, a very simple example illustrating some of the fundamental characteristics of the electrical response, most of the properties of the section including the probable, regional thickness of the hydrate zone (200 m) are assumed known from seismic and spot drilling. In the second example, less information is assumed available a priori and the complementary electrical survey is required to find both the thickness and the hydrate content in a hydrate zone about 200 m thick beneath the sea floor containing 20 and 40% hydrate in the available pore space, respectively. A linear eigenfunction analysis reveals that for these two models, the total mass of hydrate, the product of hydrate content and thickness, may be estimated to an accuracy of about 3{epsilon}% given measurements of traveltime to an accuracy of {epsilon}% over a range of separations from 100 to 1300 m. Based on these data, the author suggests that the value of {epsilon} may be of the order of 3%.
Edwards, R.N. [Univ. of Toronto, Ontario (Canada). Dept. of Physics] [Univ. of Toronto, Ontario (Canada). Dept. of Physics
Polarity reversals and tilt of the Earth's magnetic dipole
There is evidence that the terrestrial magnetic field is connected with the Earth's mantle: (1) there are magnetic anomalies that do not take part in the westward drift of the main field, but are fixed with respect to the mantle; (2) the geomagnetic pole position flips in a particular way by preferred meridional paths during a reversal; and (3) magnetic polarity reversals are correlated with the activations of geological processes. These facts may be explained if we take into account that a significant horizontal temperature gradient can exist in the top levels of the liquid core because of the different thermoconductivity of the different areas of the core-mantle boundary. These temperature inhomogeneities can penetrate the core because fluxes along the core boundary (the thermal wind) can be strongly suppressed by a small redistribution of the chemical composition in the top of the core. The nonparallel gradients of the temperature, density, and composition on the top of the core create a curled electric field that produces a current and a magnetic field. This seed-field can be amplified by motions in the core. The resulting field does not forget the seed-field distribution and in this way the field on the Earth surface (that can be created only in regions with high conductivity, i.e. in the core) is connected with the core-mantle boundary. Contrary to the usual approach to the dynamo problem, we will take into account that the seed field of thermoelectric origin is acting not only at some initial moment of time but permanently.
Dolginov, A. Z.
Complete Electric Dipole Strength and Neutron Skin in 208Pb
Small-angle polarized proton scattering including 0� on 208Pb has been studied at the RCNP cyclotron with high energy resolution of the order 25 -- 30 keV (FWHM). The complete E1 strength distribution from 5 to 20 MeV could be extracted from the data. The total E1 polarizability as well as the properties of the pygmy dipole resonance can be extracted with high precision providing important experimental constraints on the neutron skin thickness in 208Pb and the symmetry energy of neutron matter.
von Neumann-Cosel, P.; Poltoraska, I.; Tamii, A.
On the electric dipole moments of small sodium clusters from different theoretical approaches
The dipole moments of Nan clusters in the size range 10 < n < 20, recently measured at very low temperature (20 K), are much smaller than predicted by standard density functional methods. On the other hand, the calculated static dipole polarizabilities in that range of sizes deviate non-systematically from the measured ones, depending on the employed first principles approach. In this work we calculate the dipole moments and polarizabilities of a few isomers of Nan clusters of selected sizes (n = 13, 14, 16), obtained recently through an extensive unbiased search of the global minimum structures, and using density functional theory methods as well as ab initio MP2, CASSCF, and MR-CI methods. Among the density functional approaches, we consider the usual local density and generalized gradient approximations, as well as a recent van der Waals self-consistent functional accounting for non-local dispersion interactions. Both non-local pseudopotentials and all-electron implementations are employed and compared in order to assess the possible contribution of the core electrons to the electric dipole moments. Our new geometries possess significantly smaller electric dipole moments than previous density functional results, mostly when combined with the van der Waals exchange-correlation functional. However, although the agreement with experiment clearly improves upon previous calculations, the theoretical dipole moments are still about one order of magnitude larger than the experimental values, suggesting that the correct global minimum structures have not been located yet.
Aguado, Andr�s; Largo, Antonio; Vega, Andr�s; Balb�s, Luis Carlos
Electron and neutron electric dipole moments in the focus point scenario of the supergravity model
We estimate the electron and neutron electric dipole moments in the focus point scenario of the minimal SUGRA model corresponding to large sfermion masses and moderate to large tan{beta}. There is a viable region of moderate fine-tuning in the parameter space, around tan{beta}{approx_equal}5, where the experimental limits on these electric dipole moments can be satisfied without assuming unnaturally small phase angles. But the fine-tuning constraints become more severe for tan{beta}{gt}10.
Chattopadhyay, Utpal; Ibrahim, Tarek; Roy, D. P.
We study the electric and chromoelectric dipole moments of the top quark in the general two Higgs doublet model (model III). We analyze the dependency of this quantity on the new phases coming from the complex Yukawa couplings and masses of charged and neutral Higgs bosons. We observe that the electric and chromoelecric dipole moments of the top quark are of the order of 10-21 e cm and 10-20 gs cm, which are extremely large values compared to the ones calculated in the standard model and also in the two Higgs doublet model with real Yukawa couplings.
Iltan, E. O.
b-quark electric dipole moment in the general two- and three-Higgs-doublet models
We study the electric dipole moment of a b-quark in the general two-Higgs-doublet model (model III) and three-Higgs-doublet model with O(2) symmetry in the Higgs sector. We analyse the dependence of this quantity on the new phase coming from the complex Yukawa couplings and masses of charged and neutral Higgs bosons. We see that the electric dipole moment of a b-quark is of the order of 10-20 e cm, which is an extremely large value compared with that calculated in the standard model and also the two-Higgs-doublet model (model II) with real Yukawa couplings.
Electric dipole response of 208Pb and constraints on the symmetry energy
The electric dipole (E1) response of 208Pb has been precisely determined by measuring polarized proton inelastic scattering at very forward angles including zero degrees. The electric dipole polarizability, that is defined as the inverse energy-weighted sum rule of the E1 reduced transition strength, has been extracted as ?D = 20.1 �0.6 fm3. A constraint band has been extracted in the plane of the symmetry energy (J) and its slope parameter (L) at the saturation density.
Tamii, A.
Search for a Permanent Electric Dipole Moment on MERCURY-199 Atoms as a Test of Time Reversal Symmetry
Optically pumped atomic oscillators driven with a modulated light source have been used to measure the Permanent Electric Dipole Moment (PEDM) of the ^{199}Hg atom. A nonzero PEDM on the ground state of ^{199} Hg would be a direct violation of time reversal symmetry. The measurement was obtained by searching for a relative shift in the resonance frequency of the processing nuclear magnetic moments when an externally applied electric field was reversed relative to an externally applied magnetic field. The null result, d(^{199} Hg) = (.3 +/- 5.7 +/- 5.0) times 10 ^{-28} ecdotcm, represents nearly a factor of 15 improvement over previous ^{199}Hg measurements, and a factor of 25 improvement in statistical uncertainty. When combined with theoretical calculations, the result sets stringent limits on possible sources of time reversal symmetry violation in atomic systems.
Jacobs, James Patrick
Proposal for a cryogenic magnetic field measurement system for SSC dipole magnets
This proposal describes the research and development required, and the subsequent fabrication of, a system capable of making integrated magnetic multipole measurements of cryogenic 40-mm-bore SSC dipole magnets utilizing a cryogenic probe. Our experience and some preliminary studies indicate that it is highly unlikely that a 16-meter-long probe can be fabricated that will have a twist below several milliradians at cryogenic temperatures. We would anticipate a twist of several milliradians just as a result of cooldown stresses. Consequently, this proposal describes a segmented 16-meter-long probe, for which we intend to calibrate the phase of each segment to within 0.1 milliradians. The data for all segments will be acquired simultaneously, and integrated data will be generated from the vector sums of the individual segments. The calibration techniques and instrumentation required to implement this system will be described. The duration of an integral measurement at one current is expected to be under 10 seconds. The system is based on an extrapolation of the techniques used at LBL to measure cryogenic 1-meter models of SSC magnets with a cryogenic probe. It should be noted that the expansion of the dipole bore from 40 to 50 mm may make a warm-finger device practical at a cost of approximately one quarter of the cryogenic probe. A warm quadrupole measurement system can be based upon the same principles. 5 refs., 9 figs., 1 tab.
Green, M.I.; Hansen, L.
Reversals of the solar magnetic dipole in the light of observational data and simple dynamo models
Context. Observations show that the photospheric solar magnetic dipole usually does not vanish during the reversal of the solar magnetic field, which occurs in each solar cycle. In contrast, mean-field solar dynamo models predict that the dipole field does become zero. In a recent paper it was suggested that this contradiction could be explained as a large-scale manifestation of small-scale magnetic fluctuations of the surface poloidal field. Aims: Our aim is to confront this interpretation with the available observational data. Methods: Here we compare this interpretation with Wilcox Solar Observatory (WSO) photospheric magnetic field data in order to determine the amplitude of magnetic fluctuations required to explain the phenomenon and to compare the results with predictions from a simple dynamo model which takes these fluctuations into account. Results: We demonstrate that the WSO data concerning the magnetic dipole reversals are very similar to the predictions from our very simple solar dynamo model, which includes both mean magnetic field and fluctuations. The ratio between the rms value of the magnetic fluctuations and the mean field is estimated to be about 2, in reasonable agreement with estimates from sunspot data. The reversal epoch, during which the fluctuating contribution to the dipole is larger than that from the mean field, is about 4 months. The memory time of the fluctuations is about 2 months. Observations demonstrate that the rms of the magnetic fluctuations is strongly modulated by the phase of the solar cycle. This gives additional support to the concept that the solar magnetic field is generated by a single dynamo mechanism rather than also by independent small-scale dynamo action. A suggestion of a weak nonaxisymmetric magnetic field of a fluctuating nature arises from the analysis, with a lifetime of about 1 year. Conclusions: The behaviour of the magnetic dipole during the reversal epoch gives valuable information about details of solar dynamo action.
Pipin, V. V.; Moss, D.; Sokoloff, D.; Hoeksema, J. T.
Performance analysis of HD1: a 16 Tesla Nb3Sn dipole magnet
The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has been developing technology for high field accelerator magnets from brittle conductors. HD1 is a single bore block dipole magnet using two, double-layer Nb3Sn flat racetrack coils. The magnet was tested in October 2003 and reached a bore peak field of 16 T (94.5% of short sample). The average quench
S. Mattafirri; S. E. Bartlett; P. A. Bish; S. Caspi; D. R. Dietderich; P. Ferracin; S. A. Gourlay; C. R. Hannaford; A. R. Hafalia; W. G. Lau; A. F. Lietzke; A. D. McInturff; M. Nyman; G. L. Sabbi; R. M. Scanlan
Upper limit on the magnetic dipole contribution to the 5p-8p transition in Rb by use of ultracold atom spectroscopy
We report on hyperfine-resolved spectroscopic measurements of the electric-dipole-forbidden 5p3/2?8p1/2 transition in a sample of ultracold R87b atoms. The hyperfine selection rules enable the weak magnetic dipole (M1) contribution to the transition strength to be distinguished from the much stronger electric quadrupole (E2) contribution. An upper limit on the M1 transition strength is determined that is about 50 times smaller than an earlier experimental determination. We also calculate the expected value of the M1 matrix element and find that it is less than the upper limit extracted from the experiment.
Pires, R.; Ascoli, M.; Eyler, E. E.; Gould, P. L.; Derevianko, A.
Bipolar and unipolar tests of 1. 5m model SSC collider dipole magnets at Fermilab
Tests have been performed at Fermilab on 1.5 m magnetic length model SSC collider dipoles using both bipolar and unipolar ramp cycles. Hysteresis energy loss due to superconductor and iron magnetization and eddy currents is measured and compared as a function of various ramp parameters. Additionally, magnetic field measurements have been performed for both unipolar and bipolar ramp cycles. Measurements such as these will be used to estimate the heat load during collider injection for the SSC High Energy Booster dipoles. 9 refs., 4 figs.
Lamm, M.J.; Ozelis, J.P.; Coulter, K.J.; Delchamps, S.; Jaffery, T.S.; Kinney, W.; Koska, W.; Strait, J.; Wake, M. (Fermi National Accelerator Lab., Batavia, IL (USA)); Fortunato, D.; Johnson, D.E. (Superconducting Super Collider Lab., Dallas, TX (USA))
Quench performance of Fermilab/General Dynamics built full length SSC collider dipole magnets
In this paper we present results of quench testing of full length SSC dipole magnets at Fermilab. The data are from the first six of a series of thirteen 15 m long, 50 mm aperture SSC dipole magnets which are being built and tested at Fermilab. These magnets were designed jointly by Fermilab, Brookhaven Laboratory, Lawrence Berkeley Laboratory and the SSC laboratory. Among the major goals for this series of magnets are to transfer magnet production technology to the lead vendor for the Collider Dipole Magnet, the General Dynamics Corporation, and to demonstrate industrial production by the vendor. The first magnet in the series, DCA311, was built by Fermilab technicians to establish assembly procedures. The second magnet, DCA312, was the ``technology transfer magnet`` and was built jointly by Fermilab and General Dynamics technicians. The next seven, DCA313- 319 are being built by General Dynamics personnel using Fermilab facilities and procedures. However, Fermilab personnel still operate the major tooling, provide the welders, perform assembly of items that would not be part of production magnets (e.g. voltage taps), and oversee the QA program. Five of these 7 GD-built magnets will be used in the Accelerator Systems String Test (ASST) to be carried out in Dallas later this year. The last four magnets, DCA320-323, are being built by Fermilab alone.
Strait, J.; Orris, D.; Mazur, P.O.; Bleadon, M.; Bossert, R.; Carson, J.; Delchamps, S.W.; Gourlay, S.; Hanft, R.; Koska, W.; Kuchnir, M.; Lamm, M.J.; Ozelis, J.; Wake, M. [Fermi National Accelerator Lab., Batavia, IL (United States); Devred, A.; DiMarco, J.; Kuzminski, J.; Nah, W.; Ogitsu, T.; Puglisi, M.; Tompkins, J.C.; Yu, Y.; Zhao, Y.; Zheng, H. [Superconducting Super Collider Lab., Dallas, TX (United States)
In this paper we present results of quench testing of full length SSC dipole magnets at Fermilab. The data are from the first six of a series of thirteen 15 m long, 50 mm aperture SSC dipole magnets which are being built and tested at Fermilab. These magnets were designed jointly by Fermilab, Brookhaven Laboratory, Lawrence Berkeley Laboratory and the SSC laboratory. Among the major goals for this series of magnets are to transfer magnet production technology to the lead vendor for the Collider Dipole Magnet, the General Dynamics Corporation, and to demonstrate industrial production by the vendor. The first magnet in the series, DCA311, was built by Fermilab technicians to establish assembly procedures. The second magnet, DCA312, was the ''technology transfer magnet'' and was built jointly by Fermilab and General Dynamics technicians. The next seven, DCA313- 319 are being built by General Dynamics personnel using Fermilab facilities and procedures. However, Fermilab personnel still operate the major tooling, provide the welders, perform assembly of items that would not be part of production magnets (e.g. voltage taps), and oversee the QA program. Five of these 7 GD-built magnets will be used in the Accelerator Systems String Test (ASST) to be carried out in Dallas later this year. The last four magnets, DCA320-323, are being built by Fermilab alone.
Strait, J.; Orris, D.; Mazur, P.O.; Bleadon, M.; Bossert, R.; Carson, J.; Delchamps, S.W.; Gourlay, S.; Hanft, R.; Koska, W.; Kuchnir, M.; Lamm, M.J.; Ozelis, J.; Wake, M. (Fermi National Accelerator Lab., Batavia, IL (United States)); Devred, A.; DiMarco, J.; Kuzminski, J.; Nah, W.; Ogitsu, T.; Puglisi, M.; Tompkins, J.C.; Yu, Y.; Zhao, Y.; Zheng, H. (Superconducting Super Collider Lab., Dallas, TX (United States))
Spin Ice Behavior in Ising Pyrochlore Magnets with Long Range Dipole Interactions
Recent experiments suggest that the Ising pyrochlore magnets Ho_2Ti_2O7 and Dy_2Ti_2O7 display qualitative properties of the ferromagnetic nearest neighbor spin ice model proposed by Harris et al., Phys. Rev. Lett. 79, 2554 (1997). The manifestation of spin ice behavior in these systems, despite the energetic constraints introduced by the strength and the long range nature of dipole-dipole interactions, remains difficult
Michel Gingras; Roger Melko; Byron den Hertog
Molecular Expressions: Electricity and Magnetism
This is a collection of introductory tutorials and interactive simulations pertaining to electricity and magnetism. The resources are appropriate for beginners and non-science majors, covering topics that include capacitance, inductance, resistance, batteries, generators and motors, and biographical histories of pioneers in electromagnetism. Tutorials are paired with interactive Java simulations designed to enhance understanding of the physics relating to devices such as transformers, AC and DC generators, computer hard drives, pulse magnets, transistors, and more. This item is part of a larger collection of materials on optics, microscopy, electricity, and magnetism developed by the National High Magnetic Field Laboratory and Florida State University.
Davidson, Michael
Tests of 40 mm SSC dipole model magnets with vertically split yokes.
Several 1 meter long, 40 mm aperture model SSC dipole magnets with vertically split yokes have been built and tested at Fermilab. In addition to the yoke design, these magnets were used to evaluate several variants of the collet clamps which apply prestre...
W. Koska R. Bossert K. J. Coulter S. Delchamps S. Gourlay
Experimental evaluation of vertically versus horizontally split yokes for SSC dipole magnets.
The yoke in SSC dipole magnets provides mechanical support to the collared coil as well as serving as a magnetic element. The yoke and skin are used to increase the coil prestress and reduce collar deflections under excitation. Yokes split on the vertical...
J. Strait K. Coulter T. Jaffery J. Kerby W. Koska
Collaborative Simulation and Testing of the Superconducting Dipole Prototype Magnet for the FAIR Project
The superconducting dipole prototype magnet of the collector ring for the Facility for Antiproton and Ion Research (FAIR) is an international cooperation project. The collaborative simulation and testing of the developed prototype magnet is presented in this paper. To evaluate the mechanical strength of the coil case during quench, a 3-dimensional (3D) electromagnetic (EM) model was developed based on the
Zhu Yinfeng; Zhu Zhe; Xu Houchang; Wu Weiyue
Investigation of Magnetization Behavior of Nb3Sn Wires for the Next European Dipole (NED) Activity
In the frame of the conductor development for the Next European Dipole (NED), magnetization measurements are an important tool for understanding the capability of a conductor to transport current. The measurement of the magnetic momentum in parallel and transverse field gives direct information about the content of Nb3Sn as well as other superconducting phases and about the critical current density.
Michela Greco; Cristina Bernini; Pasquale Fabbricatore; Carlo Ferdeghini; Umberto Gambardella; Riccardo Musenich
Design and Test of a Nb3Sn Subscale Dipole Magnet for Training Studies
As part of a collaboration between CEA/Saclay and the Superconducting Magnet Group at LBNL, a subscale dipole structure has been developed to study training in Nb3Sn coils under variable pre-stress conditions. This design is derived from the LBNL Subscale Magnet and relies on the use of identical Nb{sub 3}Sn racetrack coils. Whereas the original LBNL subscale magnet was in a dual bore 'common-coil' configuration, the new subscale dipole magnet (SD) is assembled as a single bore dipole made of two superposed racetrack coils. The dipole is supported by a new mechanical structure developed to withstand the horizontal and axial Lorentz forces and capable of applying variable vertical, horizontal and axial preload. The magnet was tested at LBNL as part of a series of training studies aiming at understanding of the relation between pre-stress and magnet performance. Particular attention is given to the coil ends where the magnetic field peaks and stress conditions are the least understood. After a description of SD design, assembly, cool-down and tests results are reported and compared with the computations of the OPERA3D and ANSYS magnetic and mechanical models.
Felice, Helene; Caspi, Shlomo; Dietderich, Daniel R.; Felice, Helene; Ferracin, Paolo; Gourlay, Steve A.; Hafalia, Aurelo R.; Lietzke, Alan F.; Mailfert, Alain; Sabbi, GainLuca; Vedrine, Pierre
Studies of time dependence of fields in Tevatron superconducting dipole magnets
The time variation in the magnetic field of a model Tevatron dipole magnet at constant excitation current has been studied. Variations in symmetry allowed harmonic components over long time ranges show a log t behavior indicative of flux creep. Both short time range and long time range behavior depend in a detailed way on the excitation history. Similar effects are
R. W. Hanft; B. C. Brown; D. A. Herrup; M. J. Lamm; A. D. McInturff; M. J. Syphers
Disk Formation by Asymptotic Giant Branch Winds in Dipole Magnetic Fields
We present a simple, robust mechanism by which an isolated star can produce an equatorial disk. The mechanism requires that the star have a simple dipole magnetic field on the surface and an isotropic wind acceleration mechanism. The wind couples to the field, stretching it until the field lines become mostly radial and oppositely directed above and below the magnetic
Sean Matt; Bruce Balick; Robert Winglee; Anthony Goodson
Interaction of a Supersonic Plasma Stream with a Dipole Magnetic Field
A laboratory experiment is described which simulates some aspects of the inter- action of the solar wind and the geomagnetic field. In this experiment, a Mach 2 hydrogen plasma stream from a pulsed coaxial gun was directed against a dipole magnetic field. The shape of the windward side of the magnetic cavity and the circulation of the sheet currents in
J. B. Cladis; T. D. Miller; J. R. Baskett
Correction of the persistent current effect in Nb3Sn dipole magnets
The paper describes a method and results of simulation of persistent current effect in high field Nb3Sn dipole magnets being developed for the future hadron colliders. Simple and effective techniques of passive correction of the persistent current effect in superconducting accelerator magnets are proposed. Using of these techniques allows a significant reduction of sextupole and decapole field components induced by
X-ray emission from a neutron star with a strong magnetic dipole field
The accretion of matter by a neutron star with a strong magnetic dipole field is considered as a model of X-ray sources. The structure of two narrow magnetic polar cones, along which matter falls down to the stellar surface, has been studied in detail. It is shown that the cone is optically thick and that the photon diffusion time is
H. Inoue
Experimental Investigation of Axial Plasma Injection into a Magnetic Dipole Field
A high-density helium plasma, accelerated from a conical pinch, is injected axially into a magnetic dipole field. Magnetic probe measurements show that, near the axis, a compression of the field is super-imposed on the standard diamagnetic depression. The compression starts downstream and moves towards the injector. Simultaneously with the compression, an increase in the electron temperature and reflection of a
V. O. Jensen
New experimental results from the investigation of a model superferric Nuclotron-type dipole and quadrupole magnets are presented. The magnets operate at pulse repetition rate f = 1 Hz, providing the peak magnetic field B = 2 T and the field gradient G = 34 T\\/m in the dipoles and quadrupoles respectively. The superconducting coil is made from a hollow multi-filamentary
A. Kovalenko; N. Agapov; V. Bartenev; A. Donyagin; I. Eliseeva; H. Khodzhibagiyan; G. Kuznetsov; A. Smirnov; M. Voevodin; G. Moritz
Features of multi-dipole magnetic field structures in CP stars
Ten of the sixty investigated magnetic stars have two- or three-dipole structures. From the viewpoint of the relic hypothesis a wide variety of magnetic field structures and strengths allows to assume that in the initial phases of formation of magnetic stars, their fields were even more entangled and heterogeneous than now. This may be due to the complex structure of protostellar clouds, the consequence of non-stationary processes during the collapse, and, probably, the result of subsequent accretion interactions. The expected variation of the large-scale structure with age is lost at the background of a wide variety of structures, depending on the initial conditions. Complex structures occur both in the stars at ZAMS, and in the stars leaving the Main Sequence. As a result of quadratic dependence of the magnetic structure lifetime on their characteristic dimensions, large-scale configurations can exist for times comparable to the lifetime of stellar magnetic field, i.e. ? ? 109 yrs. One of the common properties of multi-dipole stars is that the centers of the dipoles are predominantly located in the equatorial plane of rotation. In the majority of studied objects magnetic dipoles (i.e. the regions with the maximum field) are shifted from the center of the star by the distance greater than the radius of the convective core (approximately 0.1 R*). This may indicate that the poloidal field is not compatible with the convective core and is not generated therein. Large distances between the monopoles, comparable to the radii of the stars are typical. This may be a sign indicating that inside the stars the field structure is slightly different from the dipole, what implies that the dipole is not a mathematical point, but rather some highly magnetized volume inside the star, comparable to a magnetized rod.
Glagolevskij, Yu. V.
Modeling ULF waves in a compressed dipole magnetic field
This paper presents the results of a linear model for global scale magneto-hydrodynamic (MHD) waves in a compressed dipole model magnetosphere. We examine scenarios where a localized monochromatic source along the magnetopause boundary launches MHD fast mode ultralow frequency (ULF) waves into the magnetosphere, where they couple to shear Alfv�n waves. Sharply peaked field line resonance (FLR) structures are found
A. W. Degeling; R. Rankin; K. Kabin; I. J. Rae; F. R. Fenrich
Passive superconductor: A viable method of controlling magnetization multipoles in the SSC dipole
At injection, the magnetization of the superconductor produces the dominant field error in the Superconducting Super Collider (SSC) dipole magnets. The field generated by magnetization currents in the superconductor is rich in higher symmetric multipoles (normal sextupole, normal decapole, and so on). Pieces of passive superconductor properly located within the bore of the dipole magnet can cancel the higher multipoles generated by the SSC dipole coils. The multipoles generated by the passive superconductor (predominantly sextupole and decapole) are controlled by the angular and radial location of the superconductor, the volume of superconductor, and the size of the superconducting filaments within the passive conductor. This paper will present the tolerances on each of these factors. The paper will show that multipole correction using passive superconductor is in general immune to the effects of temperature and magnetization decay due to flux creep, provided that dipole superconductor and the passive correction superconductor are properly specified. When combined with a lumped correction system, the passive superconductor can be a viable alternative to continuous correction coils within the SSC dipoles.
Green, Michael A.
Tunable ratchet effects for vortices pinned by periodic magnetic dipole arrays
The ratchet effect is demonstrated theoretically for the simple model of a vortex in a thin superconducting film interacting with a periodic array of magnetic dipoles placed in the vicinity of the film . The pinning potential for the vortex is calculated in the London limit and found to break spatial inversion symmetry and to depend on the orientation of the magnetic dipole moments. The motion of the vortex at zero temperature driven by a force oscillating periodically in time is investigated numerically. Drift vortex motion consisting of displacements by a translation vector of the dipole array during each period of oscillation is obtained and studied in detail. The direction of drift differs in general from that of the driving force, except if the driving force oscillates in a direction of high symmetry of the dipole array. The vortex drift velocity depends on the orientation of the magnetic moments, and can be tuned by rotating the dipoles. It is pointed out that if the magnetic moments are free to rotate, the ratchet effect can be produced and tuned by a magnetic field applied parallel to the film surfaces.
At injection, the magnetization of the superconductor produces the dominant field error in the SSC dipole magnets. The field generated by magnetization currents in the superconductor is rich in higher symmetric multipoles (normal sextupole, normal decapole, and so on). Pieces of passive superconductor properly located within the bore of the dipole magnet can cancel the higher multipoles generated by the SSC dipole coils. The multipoles generated by the passive superconductor (predominantly sextupole and decapole) are controlled by the angular and radial location of the superconductor, the volume of superconductor, and the size of the superconducting filaments within the passive conductor. This paper will present the tolerances on each of these factors. The paper will show that multipole correction using passive superconductor is in general immune to the effects of temperature and magnetization decay due to flux creep, provided that dipole superconductor and the passive correction superconductor are properly specified. When combined with a lumped correction system, the passive superconductor can be a viable alternative to continuous correction coils within the SSC dipoles. 20 refs., 8 figs., 2 tabs.
A robust limit for the electric dipole moment of the electron
Electric dipole moments constitute a competitive method to search for new physics, being particularly sensitive to new CP -violating phases. Given the experimental and theoretical progress in this field and more generally in particle physics, the necessity for more reliable bounds than the ones usually employed emerges. We therefore propose an improved extraction of the electric dipole moment of the electron and the relevant coefficient of the electron-nucleon coupling, taking into account theoretical uncertainties and possible cancellations, to be used in model-dependent analyses. Specifically, we obtain at 95% C.L. | d e | ? 0.14 � 10-26 e cm with present data, which is very similar to the bound typically quoted from the YbF molecule, but obtained in a more conservative manner. We examine furthermore in detail the prospects for improvements and derive upper limits for the dipole moments of several paramagnetic systems presently under investigation, i.e. cesium, rubidium and francium.
Jung, Martin
Atomic-scale study of electric dipoles near charged and uncharged domain walls in ferroelectric films.
Ferroelectrics are materials exhibiting spontaneous electric polarization due to dipoles formed by displacements of charged ions inside the crystal unit cell. Their exceptional properties are exploited in a variety of microelectronic applications. As ferroelectricity is strongly influenced by surfaces, interfaces and domain boundaries, there is great interest in exploring how the local atomic structure affects the electric properties. Here, using the negative spherical-aberration imaging technique in an aberration-corrected transmission electron microscope, we investigate the cation-oxygen dipoles near 180 degrees domain walls in epitaxial PbZr(0.2)Ti(0.8)O(3) thin films on the atomic scale. The width and dipole distortion across a transversal wall and a longitudinal wall are measured, and on this basis the local polarization is calculated. For the first time, a large difference in atomic details between charged and uncharged domain walls is reported. PMID:18066068
Jia, Chun-Lin; Mi, Shao-Bo; Urban, Knut; Vrejoiu, Ionela; Alexe, Marin; Hesse, Dietrich
Updating the neutron electric dipole moment in a fourth generation standard model
A fourth generation of quarks, if it exists, may provide sufficient CP violation for the baryon asymmetry of the Universe. We estimate the neutron electric dipole moment in the presence of a fourth generation and find it would be dominated by the strange quark chromoelectric dipole moment, assuming it does not get wiped out by a Peccei-Quinn symmetry. Both the three electroweak loop and the two-loop electroweak/one-loop gluonic contributions are considered. With m{sub b'}, m{sub t'} at 500 GeV or so that can be covered at the LHC, and with a Jarlskog CP violation factor that is consistent with hints of New Physics in b{yields}s transitions, the neutron electric dipole moment is found around 10{sup -31}e cm, still far below the 10{sup -28}e cm reach of the new experiments being planned or under construction.
Hisano, Junji [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); IPMU, TODIAS, University of Tokyo, Kashiwa, 277-8583 (Japan); Hou, Wei-Shu [Department of Physics, National Taiwan University, Taipei, Taiwan 10617 (China); National Center for Theoretical Sciences, National Taiwan University, Taipei, Taiwan 10617 (China); Xu Fanrong [Department of Physics, National Taiwan University, Taipei, Taiwan 10617 (China)
A fourth generation of quarks, if it exists, may provide sufficient CP violation for the baryon asymmetry of the Universe. We estimate the neutron electric dipole moment in the presence of a fourth generation and find it would be dominated by the strange quark chromoelectric dipole moment, assuming it does not get wiped out by a Peccei-Quinn symmetry. Both the three electroweak loop and the two-loop electroweak/one-loop gluonic contributions are considered. With mb', mt' at 500 GeV or so that can be covered at the LHC, and with a Jarlskog CP violation factor that is consistent with hints of New Physics in b?s transitions, the neutron electric dipole moment is found around 10-31ecm, still far below the 10-28ecm reach of the new experiments being planned or under construction.
Hisano, Junji; Hou, Wei-Shu; Xu, Fanrong
Spectrum analysis of the power line flicker induced by the electrical test of the prototype Booster dipole.
Testing of the prototype Booster dipole magnet at full current produced measurable disturbances of the beam position at the National Synchrotron Light Source. Power for the magnet and the NSLS are distributed from three substation transformers at Temple P...
M. Meth
Electric and Magnetic Forces: Electric Charges
Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach.This Science Object is the first of three Science Objects in the Electric and Magnetic Forces SciPack.
National Science Teachers Association (NSTA)
Determination of Nanocrystal Size Distribution in Magnetic Multicore Particles Including Dipole-Dipole Interactions and Magnetic Anisotropy: a Monte Carlo Study
A correct estimate of the size distribution (i.e., median diameter D and geometric standard deviation ?) of the magnetic nanocrystals (MNCs) embedded in magnetic multicore particles is a necessity in most applications relying on the magnetic response of these particles. In this paper we use a Monte Carlo method to simulate the equilibrium magnetization of two types of multicore particles: (I) MNCs fused in a random compact cluster, and (II) MNCs distributed on the surface of a large carrier sphere. The simulated magnetization data are then fitted using a common method based on a Langevin equation weighted with a size distribution function. Finally, the fitting parameters Dm and ?m are compared to the real parameters Dp and ?p used to generate the MNCs. Our results show that fitting magnetization data with a Langevin model that neglects magnetic anisotropy and dipole-dipole interactions leads to an erroneous estimate of the size distribution of the MNCs in multicore particles. The magnitude of the error depends on the particle morphology, number of MNCs contained in the particle and magnetic properties of the MNCs.
Schaller, Vincent; Wahnstr�m, G�ran; Sanz-Velasco, Anke; Enoksson, Peter; Johansson, Christer
Neutron Electric Dipole Moment in the Standard Model: Complete Three-Loop Calculation of the Valence Quark Contributions
We present a complete three-loop calculation of the electric dipole moment of the u and d quarks in the standard model. For the d quark, more relevant for the experimentally important neutron electric dipole moment, we find cancellations which lead to an order of magnitude suppression compared with previous estimates. {copyright} {ital 1997} {ital The American Physical Society}
Czarnecki, A.; Krause, B. [Institut fuer Theoretische Teilchenphysik, Universitaet Karlsruhe, D-76128 Karlsruhe (Germany)] [Institut fuer Theoretische Teilchenphysik, Universitaet Karlsruhe, D-76128 Karlsruhe (Germany)
Magnetic dipole moment of a spherical shell with TRM acquired in a field of internal origin. [Thermoremanent Magnetization implications for lunar magnetic field
The acquisition of thermoremanent magnetization (TRM) by a cooling spherical shell is studied for internal magnetizing dipole fields, using Runcorn's (1975) theorems on magnetostatics. If the shell cools progressively inward, inner regions acquire TRM in a net field composed of the dipole source term plus a uniform field due to the outer magnetized layers. In this case, the global dipole moment and external remanent field are nonzero when the whole shell has cooled below the Curie point and the source dipole has disappeared. The remanent field outside the shell is found to depend on the thickness, radii, and cooling rate of the shell, as well as the coefficient of TRM and the intensity of the magnetizing field. Some implications for the moon's remanent dipole moment are discussed.
Srnka, L. J.
Quantifying and controlling the magnetic dipole contribution to 1.5-?m light emission in erbium-doped yttrium oxide
We experimentally quantify the contribution of magnetic dipole (MD) transitions to the near-infrared light emission from trivalent erbium-doped yttrium oxide (Er3+:Y2O3). Using energy-momentum spectroscopy, we demonstrate that the 4I13/2?4I15/2 emission near 1.5 ?m originates from nearly equal contributions of electric dipole (ED) and MD transitions that exhibit distinct emission spectra. We then show how these distinct spectra, together with the differing local density of optical states for ED and MD transitions, can be leveraged to control Er3+ emission in structured environments. We demonstrate that far-field emission spectra can be tuned to resemble almost pure emission from either ED or MD transitions and show that the observed spectral modifications can be accurately predicted from the measured ED and MD intrinsic emission rates.
Li, Dongfang; Jiang, Mingming; Cueff, S�bastien; Dodson, Christopher M.; Karaveli, Sinan; Zia, Rashid
Schiff Theorem and the Electric Dipole Moments of Hydrogen-Like Atoms
The Schiff theorem is revisited in this work and the residual P- and T-odd electron-nucleus interaction, after the shielding takes effect, is completely specified. An application is made to the electric dipole moments of hydrogen-like atoms, whose qualitative features and systematics have important implication for realistic paramagnetic atoms.
Liu, C.-P. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Haxton, W. C. [INT, Univ. of Washington, Box 351550, Seattle, WA 98195-1550 (United States); Dept. of Physics, Univ. of Washington, Box 351550, Seattle, WA 98195-1550 (United States); Ramsey-Musolf, M. J. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Timmermans, R. G. E.; Dieperink, A. E. L. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands)
Fluid simulation of the collisionless plasma sheath surrounding an electric dipole antenna in the inner magnetosphere
The electrostatic sheath formation surrounding an electric dipole antenna at very low frequencies (VLF) in a magnetoplasma is examined through numerical simulation. In this paper, a hydrodynamic approach is used to solve for the nonlinear sheath dynamics of antennas located in plasmas similar to that which exists in the plasmasphere between L = 2 and L = 3 in the
T. W. Chevalier; T. F. Bell
Power loss of an oscillating electric dipole in a quantum plasma
A system of linearized quantum plasma equations (quantum hydrodynamic model) has been used for investigating the dispersion equation for electrostatic waves in the plasma. Furthermore, dispersion relations and their modifications due to quantum effects are used for calculating the power loss of an oscillating electric dipole. Finally, the results are compared in quantum and classical regimes.
Ghaderipoor, L. [Department of Physics, Faculty of Science, University of Qom, 3716146611 (Iran, Islamic Republic of); Mehramiz, A. [Department of Physics, Faculty of Science, Imam Khomeini Int'l University, Qazvin 34149-16818 (Iran, Islamic Republic of)
Investigation of anomalous K, L and M shell conversion in electric dipole transitions
Anomalous experimental conversion coefficients of theK, L andM subshells are investigated for thirteen highly hindered electric dipole transition in six deformed odd mass nuclei. For a distinct nuclear transition, all experimental anomalies are consistent with one parameter, containing all nuclear information. The values of this parameter are determined and a simple connection with the hindrance of the transition seems to
Hans-Christian Pauli; Kurt Alder
Transient electromagnetic field generated by a vertical electric dipole on the surface of a dissipative earth
The problem of electromagnetic pulse propagation over a dissipative earth surface, excited by a vertical electric dipole located on the earth surface, is investigated. By deforming related integrals in the complex frequency domain it is shown that the scattering contribution of the earth, which is formally expressed in terms of several double inf'mite integrals, can be efficiently computed from some
Hussain Haddad; D. C. Chang
A unified theory on radiation of a vertical electric dipole above a dissipative earth
Analytical expressions are derived for the electromagnetic field associated with a vertical electric dipole above a dissipative earth. The scattered field is shown to consist of a direct contribution from a perfect image source, and a correction due to the finite conductivity of earth which is expressible in terms of an incomplete Hankel function. The resultant expression readily reduces to
D. C. Chang; R. J. Fisher
Application of the contour transformation method to a vertical electric dipole over Earth
A contour transformation method is applied to the computation of the Sommerfeld integral associated with a vertical electric dipole above Earth. In this method the slowly varying part of the transformed Sommerfeld integrand is approximated by a few exponential terms using Prony's method. The resulting integrals are then carried out analytically, thereby, yielding incomplete Lipschitz-Hankel integrals. Therefore numerical integration of
Steven L. Dvorak; Mehdi M. Mechaik
Violation of Cp Invariance and the Electric Dipole Moment of the Neutron.
On the basis of the model of CP violation recently proposed (see AD-650 951), the static electric dipole moment of the neutron is calculated. The result is: the absolute value of (mu-ed/e) = the absolute value of D approx. = (9 x 10 to the -22 power cm). ...
K. Nishijima L. J. Swank
Proton conduction related electrical dipole and space charge polarization in hydroxyapatite
Hydroxyapatite (HAp), well known as a biomaterial, is also known as a proton conductor. Its electrical properties are related strongly to its stability and surface properties. In particular, persistent electrical polarization related to proton conductivity of hydroxyapatite has a substantial influence on hydroxyapatite surface properties. The origins of polarizations were investigated in proton-defect-induced HAp ceramics using thermally stimulated depolarization current (TSDC) measurements. Two peaks were observed, indicating that the persistent polarization comprises polarization elements of two kinds. The TSDC response as a function of the applied electric field in polarization treatments indicated that the persistent polarization is dipole polarization and space charge polarization. The former, dipole polarization, increased continuously with increased defect concentration. The activation energies were 0.67-0.86 eV, which are comparable to proton conduction activation energy. Results show that dipole polarization consists of electrical dipoles of the defect pairs, which are formed through proton conduction. The activation energies of 1.01 +/- 0.01 eV for space charge polarization are independent of the defect concentration, suggesting that these originated from protons trapped at the grain boundaries as a result of long-range proton conduction. The polarization of two different types is expected to exert different effects on the HAp surface properties.
Horiuchi, N.; Nakamura, M.; Nagai, A.; Katayama, K.; Yamashita, K.
Search for an electron electric dipole moment with trapped molecular ions
The search for a permanent electron electric dipole moment (eEDM) serves as a test of fundamental symmetry violations and of physics beyond the Standard Model. Trapped molecular ions in the 3Delta 1 metastable electronic state are suitable candidates for an eEDM search due to their large effective electric fields and long electron spin coherence times. This thesis presents the quantum state manipulation and coherent spectroscopy of trapped HfF+ molecular ions in rotating bias fields for an eEDM search. The quantum state manipulation, which involves preparation of a large fraction of molecular ions in a single desired quantum state as well as rotational-state-resolved detection, is complicated by the lack of HfF+ spectroscopic information prior to the start of this thesis. We performed state preparation by first state-selectively autoionizing neutral HfF such that 35% of the HfF+ are formed in a single rovibrational level of the electronic ground state 1Sigma+, and then transferring those ions into the desired Stark levels of a single hyperfine-rovibrational manifold of the 3Delta1 state. Rotational-state-resolved detection is accomplished by both laser-induced fluorescence and resonance-enhanced multi-photon photodissociation, where the latter is preferred as the state detection method of choice because its efficiency is two orders of magnitude higher compared to LIF. With the quantum state manipulation techniques developed, we performed Ramsey spectroscopy of the trapped HfF+ ions in the presence of rotating bias electric and magnetic fields, demonstrating electron spin coherence times as long as 150 ms. Finally, we present a preliminary measurement of the eEDM at the |de| < 10-25 e cm level.
Loh, Huanqian
TOSCA calculations and measurements for the SLAC SLC damping ring dipole magnet
The SLAC damping ring dipole magnet was originally designed with removable nose pieces at the ends. Recently, a set of magnetic measurements was taken of the vertical component of induction along the center of the magnet for four different pole-end configurations and several current settings. The three dimensional computer code TOSCA, which is currently installed on the National Magnetic Fusion Energy Computer Center's Cray X-MP, was used to compute field values for the four configurations at current settings near saturation. Comparisons were made for magnetic induction as well as effective magnetic lengths for the different configurations. 1 ref., 12 figs., 2 tabs.
Early, R.A.; Cobb, J.K.
Microstructure and magnetic properties of magnetic fluids consisting of shifted dipole particles under the influence of an external magnetic field.
We investigate the structure of a recently proposed magnetic fluid consisting of shifted dipolar (SD) particles in an externally applied magnetic field via computer simulations. For standard dipolar fluids the applied magnetic field usually enhances the dipole-dipole correlations and facilitates chain formation whereas in the present system the effect of an external field can result in a break-up of clusters. We thoroughly investigate the origin of this phenomenon through analyzing first the ground states of the SD-particle systems as a function of an applied field. In a second step we quantify the microstructure of these systems as functions of the shift parameter, the effective interaction parameter, and the applied magnetic field strength. We conclude the paper by showing that with the proper choice of parameters, it is possible to create a system of SD-particles with highly interacting magnetic particles, whose initial susceptibility is below the Langevin susceptibility, and which remains spatially isotropic even in a very strong external magnetic field. PMID:24320398
Weeber, Rudolf; Klinkigt, Marco; Kantorovich, Sofia; Holm, Christian
Electromagnetic field of a vertical electric dipole in the presence of a three-layered region
The electromagnetic field generated by a vertical electric dipole in the air over the surface of a two-layered region is determined for continuous-wave excitation. The region of interest consists of a conductor or dielectric with high permittivity, coated with an electrically thin layer of a dielectric under a half-space of air. Simple explicit formulas are derived for the field at
Ronald W. P. King; Sheldon S. Sandler
The search for the neutron electric dipole moment at the Paul Scherrer Institute
The measurement of the neutron electric dipole moment (nEDM) constrains the contribution of CP-violating terms within both the Standard Model and its extensions. The experiment uses ultracold neutrons (UCN) stored in vacuum at room temperature. This technique provided the last (and best) limit by the RAL/Sussex/ILL collaboration in 2006: dn < 2:9 � 10 -26 e cm (90% C.L.). We aim to improve the experimental sensitivity by a factor of 5 within 2-3 years, using an upgrade of the same apparatus. We will take advantage of the increased ultracold neutron density at the Paul Scherrer Institute (PSI) and of a new concept including both, external magnetometers and a cohabiting magnetometer. In parallel, a next generation apparatus with two UCN storage chambers and an elaborate magnetic field control is being designed aiming to achieve another order of magnitude increase in sensitivity, allowing us to put a limit as tight as dn < 5 � 10 -28 e cm (95% C.L.), if not establishing a finite value.
Baker, C. A.; Ban, G.; Bodek, K.; Burghoff, M.; Chowdhuri, Z.; Daum, M.; Fertl, M.; Franke, B.; Geltenbort, P.; Green, K.; van der Grinten, M. G. D.; Gutsmiedl, E.; Harris, P. G.; Henneck, R.; Iaydjiev, P.; Ivanov, S. N.; Khomutov, N.; Kasprzak, M.; Kirch, K.; Kistryn, S.; Knappe-Gr?uneberg, S.; Knecht, A.; Knowles, P.; Kozela, A.; Lauss, B.; Lefort, T.; Lemi`ere, Y.; Naviliat-Cuncic, O.; Pendlebury, J. M.; Pierre, E.; Piegsa, F. M.; Pignol, G.; Q�e?ener, G.; Roccia, S.; Schmidt-Wellenburg, P.; Shiers, D.; Smith, K. F.; Schnabel, A.; Trahms, L.; Weis, A.; Zejma, J.; Zenner, J.; Zsigmond, G.
On vertical electric fields at lunar magnetic anomalies
We study the interaction between a magnetic dipole mimicking the Gerasimovich magnetic anomaly on the lunar surface and the solar wind in a self-consistent 3-D quasi-neutral hybrid simulation where ions are modeled as particles and electrons as a charge-neutralizing fluid. Especially, we consider the origin of the recently observed electric potentials at lunar magnetic anomalies. An antimoonward Hall electric field forms in our simulation resulting in a potential difference of <300V on the lunar surface, in which the value is similar to observations. Since the hybrid model assumes charge neutrality, our results suggest that the electric potentials at lunar magnetic anomalies can be formed by decoupling of ion and electron motion even without charge separation.
Jarvinen, R.; Alho, M.; Kallio, E.; Wurz, P.; Barabash, S.; Futaana, Y.
Design study of 15Tesla RHQT Nb3Al block type dipole magnet
The design study of the block type 15-Tesla RHQT Nb�Al dipole magnet, and its merits over Nb�Sn magnets are presented. The copper stabilized RHQT Nb�Al strand is now becoming commercially available for the application to the accelerator magnets. A 1 mm diameter RHQT Nb�Al strand with filament size about 50 μ, non-copper Jc about 1000 A\\/mm² at 15 Tesla at
R. Yamada; G. Ambrosio; E. Barzi; V. Kashikin; A. Kikuchi; I. Novitski; T. Takeuchi; M. Wake; A. Zlobin
HD1: design and fabrication of a 16 Tesla Nb3Sn dipole magnet
The Lawrence Berkeley National Laboratory (LBNL) Superconducting Magnet Group has completed the design, fabrication and test of HD1, a 16 T block-coil dipole magnet. State of the art Nb3Sn conductor was wound in double-layer racetrack coils and supported by an iron yoke and a tensioned aluminum shell. In order to prevent conductor movement under magnetic forces up to the design
A. R. Hafalia; S. E. Bartlett; S. Caspi; L. Chiesa; D. R. Dietderich; P. Ferracin; M. Goli; S. A. Gourlay; C. R. Hannaford; H. Higley; A. F. Lietzke; N. Liggins; S. Mattafirri; A. D. McInturff; M. Nyman; G. L. Sabbi; R. M. Scanlan; J. Swanson
Quench characteristics of 5-cm-aperture, 15-m-long SSC dipole magnet prototypes
The quench performance and ramp rate sensitivity of 18 5-cm-aperture, 15-m-long Superconducting Super Collider (SSC) dipole magnet prototypes are discussed. All the magnets appear to reach a quench plateau near their extrapolated short sample current limit and well in excess of the operating current with very little training. Most of the magnets, however, exhibit a dramatic degradation of their quench
W. Nah; A. Akhmetov; M. Anerella; R. Bossert; T. Bush; J. Carson; R. Coombes; J. Cottingham; S. W. Delchamps; A. Devred; J. Di Marco; G. Ganetis; G. Garber; C. Goodzeit; A. Ghosh; S. Gourlay; A. Greene; R. Gupta; R. Hanft; A. Jain; S. Khan; E. Kelly; W. Koska; M. Kuchnir; J. Kuzminski; M. J. Lamm; P. Mantsch; P. O. Mazur; G. Morgan; J. Muratore; T. Ogitsu; D. Orris; J. Ozelis; T. Peterson; E. G. Pewitt; A. Prodell; M. Puglisi; P. Radusewicz; M. Rehak; E. P. Rohrer; J. Royet; W. Sampson; P. Sanger; R. Scanlan; R. Schermer; R. Shutt; R. Stiening; J. Strait; C. Taylor; R. Thomas; P. Thompson; J. C. Tompkins; J. Turner; M. Wake; P. Wanderer; E. Willen; Y. Yu; J. Zbasnik; Y. Zhao; H. Zheng
Test results of HD1b, an upgraded 16 tesla Nb3Sn dipole magnet
The Superconducting Magnet Group at Lawrence Berkeley National Laboratory has been developing high-field, brittle-superconductor, accelerator magnet technology, in which the conductor's support system can significantly impact conductor performance (as well as magnet training). A recent H-dipole coil test (HD1) achieved a peak bore-field of 16 Tesla, using two, flat-racetrack, double-layer Nb3Sn coils. However, its 4.5 K training was slow, with
A. F. Lietzke; S. E. Bartlett; P. Bish; S. Caspi; D. Dietderich; P. Ferracin; S. A. Gourlay; A. R. Hafalia; C. R. Hannaford; H. Higley; W. Lau; N. Liggins; S. Mattafirri; M. Nyman; G. Sabbi; R. Scanlan; J. Swanson
Development of twin aperture dipole magnets for the Large Hadron Collider
A twin aperture dipole magnet has been developed with a feature of symmetric, separate coil\\/collar design in a R&D cooperation between CERN and KEK towards the LHC (Large Hadron Collider) project. The magnet reached 8.1 T at 4.2 K and 9.6 T at 1.8 K in the training test. Development of the magnet and test results are discussed. Design study
Akira Yamamoto; Takakazu Shintomi; Nono Higashi; Hiromi Hirabayashi; Hiroshi Kawamata; Naihao Song; Akio Terashima; Hiroshi Yamaoka; Shuma Kawabata; G. Brianti; J. Buckley; D. Leroy; R. Perin; A. Siemko; L. Walckiers; M. Hirano; T. Origasa; K. Makishima; I. Inoue; M. Ikeda; S. Meguro; M. Kondo
Comparison Between Active and Passive Shielding Designs for a Large Acceptance Superconducting Dipole Magnet
Comparison between active and passive shielding magnets for a large acceptance superconducting dipole magnet has been carried out. The two magnet designs have been studied to answer to the new requirements of Nuclear Physics experiments in order to get a momentum resolution of up to 10-3 with 1 GeV\\/nucleon heavy-ion beams: A field integral of about 5Tmiddotm
Bernard Gastineau; Chhon Pes; Jean-Eric Ducret
Modification of cos ? coil shape in superconducting dipole magnets for reducing the coil size
In coil-dominated superconducting dipole magnets the coil size and hence the cost of the magnet can be reduced by optimizing the shape of the coil. We have used the variational calculus and a random search technique to show that the coil shape markedly deviates from the conventional cos ? design when one reduces the coil size while holding the field and field quality to specified values. A block-coil dipole giving a field of 7.0 T has been designed on the basis of the optimization. With iron yoke this can give a field of 8.4 T.
Sarma, P. R.; Ibomcha, N.; Bhandari, R. K.
A finite element analysis of an SSC dipole magnet (NC-9 cross-section)
Finite element methods are used to calculate the mechanical behavior of an SSC superconducting dipole magnet under different loading conditions. A two-dimensional model of the NC-9 design (aluminum collars) has been developed and used to calculate the transverse deflections and stresses in the dipole after assembly of the magnet, cooldown to 4.2 K, and energization to 6.6 T. Verification of the results with experimental measurements and observations, and limitations of the analysis, are also discussed. 6 refs., 6 figs., 2 tabs.
Chapman, M. S. [Lawrence Berkeley Lab., CA (USA). SSC Central Design Group; Wands, R. H. [Fermi National Accelerator Lab., Batavia, IL (USA)
Theoretical study of the electric dipole moment function of the ClO molecule
The potential energy function and electric dipole moment function (EDMF) are computed for ClO X 2Pi using several different techniques to include electron correlation. The EDMF is used to compute Einstein coefficients, vibrational lifetimes, and dipole moments in higher vibrational levels. The band strength of the 1-0 fundamental transition is computed to be 12 + or - 2 per sq cm atm determined from infrared heterodyne spectroscopy. The theoretical methods used include SCF, CASSCF, multireference singles plus doubles configuration interaction (MRCI) and contracted CI, coupled pair functional (CPF), and a modified version of the CPF method. The results obtained using the different methods are critically compared.
Pettersson, L. G. M.; Langhoff, S. R.; Chong, D. P.
Diamagnetic repulsion, the method of magnetic images & suitability of the solenoid and dipole models
The repulsion of a permanent magnet from a diamagnetic region was investigated. A magnet of moment m can be described by two models (i) solenoid - a circulating current of appropriate value; second (ii) a magnetic dipole comprising of a pair of north and south poles of separated by a distance.The magnetic field (B) of a permanent magnet was measured. The magnet was modeled as a solenoid with a circulating surface current. The Biot-Savart law field (B) was of computed in Matlab. The experimental data of was in excellent agreement with the Matlab results. However, for computing the repulsion force (F) between the magnet and its diamagnetic image by the direct integration of the current-current interaction require detailed knowledge of the two current densities. However such knowledge is not essential if image is modeled as a dipole. When the magnet is a distance z above the diamagnetic interface then the image current I2 gives rise to a image dipole m2 and the F � m2div B, where the div of the holding field is computed at the distance 2z below the magnet. In this model F is directly proportional to both m' and the derivative of the field and a negative slope indicates repulsion, all three were confirmed.
Yin, Ming; Zhang, Huaizhou; Datta, Timir
Magnetic field distribution of injection chicane dipoles in Spallation Neutron Source accumulator ring
We have performed 3D computing simulations to study the magnetic field distribution of the injection chicane dipoles in the SNS accumulator ring. The simulations yield the performance characteristics of the magnets and generate the magnetic field data in three dimensional grids for further beam tracking study. Based on the simulation data, a 3D multipole expansion of the chicane dipole field, consisting of the generalized gradients and their derivatives, has been made. The harmonic and pseudoharmonic components in the expansion give much insight into the magnet physics and can fit directly into theoretical frame work of beam optics. The expansion is quasianalytical by fitting numeric data into interpolation functions. A 5th-order representation of the magnetic field is generated, and the effects of even higher-order terms on the field representation are discussed.
Wang, J. G.
In a Recirculating Heavy Ion Fusion Induction Accelerator the largest energy consumption occurs in the bending magnetic fields. Because these fields are pulsed, they cannot be generated by superconducting magnets. The bending magnets will consist of iron core dipoles with multiturn copper conductors. The energy stored in the magnetic field is many tens of megajoules and over 90% of this energy must be recovered and reused to make this type of accelerator practical. To further make this approach competitive, a cost effective and reliable energy recovery system must be designed. Two similar concepts are proposed which show promise for high efficiency and reasonable cost. A small scale prototype of the pulser and dipole magnet were built and tested. The two systems and very preliminary test results of one will be described. 7 figs.
Reginato, L.; Newton, M.; Yu, S.
Theoretical Study of the Electric Dipole Moment Function of the CIO Molecule
The potential energy function and electric dipole moment function (EDMF) are computed for CIO Chi(sup 2)Pi using several different techniques to include electron correlation. The EDMF is used to compute Einstein coefficients, vibrational lifetimes, and dipole moments in higher vibrational levels. Remaining questions concerning the position of the maximum of the EDMF may be resolved through experimental measurement of dipole moments of higher vibrational levels. The band strength of the 1-0 fundamental transition is computed to be 12 +/- 2 /sq cm atm in good agreement with three experimental values, but larger than a recent value of 5 /sq cm atm determined from infrared heterodyne spectroscopy. The theoretical methods used include SCF, CASSCF, multireference singles plus doubles configuration interaction (MRCI) and contracted CI, coupled pair functional (CPF), and a modified version of the CPF method. The results obtained using the different methods are critically compared.
Pettersson, Lars G. M.; Langhoff, Stephen R.; Chong, Delano P.
Calculated electric dipole moment of NiH X2Delta
A calculated dipole moment of 2.39 D at R sub e = 2.79 a sub 0 is reported, obtained from complete active space SCF/configuration interaction calculations plus one natural orbital iteration. The calculation is in good agreement with the experimental value of 2.4 + or - 0.1 D measured for the lowest vibrational level. In agreement with Gray et al. (1985), it is found that the dipole moment is strongly correlated with the 3d electron population; the good agreement with experiment thus provides verification of the mixed state model of NiH. It is concluded that the electric dipole moment of NiH is a sensitive test of the quality of the NiH wave function.
Walch, S.; Bauschlicher, C. W., Jr.; Langhoff, S. R.
Systematic calculation of electric dipole strength with Skyrme-HF plus RPA
We undertake a systematic calculation on electric dipole responses of even-even nuclei for a wide mass region employing a fully self-consistent Hartree-Fock plus RPA approach. For an easy implementation of the fully self-consistent calculation, the finite amplitude method which we have proposed recently is employed. We calculate dipole responses in Cartesian mesh representation, which can deal with deformed nuclei but do not include pairing correlation. The systematic calculation has reached a mass Aapprox100 region. The calculated results show reasonable agreement for heavy nuclei while the average excitation energies are underestimated for light nuclei. We show a systematic comparison of calculated peak energies of giant dipole resonances, and the splitting of the peak energy with the ground state deformation.
Inakura, T. [Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8571 (Japan); Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, Wako 351-0198 (Japan); Nakatsukasa, T. [Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, Wako 351-0198 (Japan); Yabana, K. [Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8571 (Japan); Institute for Physics, University of Tsukuba, Tsukuba 305-8571 (Japan)
Electric and Magnetic Forces
SciGuides are a collection of thematically aligned lesson plans, simulations, and web-based resources for teachers to use with their students centered on standards-aligned science concepts. People have known about and experienced electricity an
AC loss measurements of model and full size 50mm SSC collider dipole magnets at Fermilab
Tests have recently been performed at Fermilab in order to measure the energy losses due to eddy currents and iron and superconductor magnetization. These measurements were performed on six 1.5m long model magnets and eight 15m long full scale collider dipole magnets. AC losses were measured as a function of ramp rate using sawtooth ramps from 500, to 5000 Amps for both types of magnets, while bipolar studies were additionally performed on some of the short magnets. The measured magnet voltage and current for a complete cycle are digitally integrated to yield the energy loss per cycle. Measurement reproducibility is typically 5%, with good agreement between long magnet measurements and extrapolations from short magnet measurement results. Magnetization loss measurements among similar magnet types agree to within experimental error, while eddy current losses correlate strongly with the observed dependence of quench current on ramp rate.
Ozelis, J.P.; Delchamps, S.W.; Gourlay, S.; Jaffery, T.; Kinney, W.; Koska, W.; Kuchnir, M.; Lamm, M.J.; Mazur, P.O.; Orris, D.; Strait, J.; Wake, M. (Fermi National Accelerator Lab., Batavia, IL (United States)); Dimarco, J.; Kuzminski, J.; Zheng, H. (Superconducting Super Collider Lab., Dallas, TX (United States))
The concept of correction of the magnetization sextupole became a topic of discussion as soon as it was realized that superconductor magnetization could have a serious effect on the SSC beam during injection. Several methods of correction were proposed. These included (1) correction with active bore tube windings like those on the HERA machine which correct out magnetization sextupole and
M. A. Green
There is evidence that the terrestrial magnetic field is connected with the Earth's mantle: (1) there are magnetic anomalies that do not take part in the westward drift of the main field, but are fixed with respect to the mantle; (2) the geomagnetic pole position flips in a particular way by preferred meridional paths during a reversal; and (3) magnetic
A. Z. Dolginov
Calculation of the (T,P)-odd electric dipole moment of thallium and cesium
Parity and time invariance violating electric dipole moment of {sup 205}Tl is calculated using the relativistic Hartree-Fock and configuration interaction methods and the many-body perturbation theory. Contributions from the interaction of the electron electric dipole moments with internal electric field and scalar-pseudoscalar electron-nucleon (T,P)-odd interaction are considered. The results are d({sup 205}Tl)=-582(20)d{sub e} or d({sup 205}Tl)=-7.0(2)x10{sup -18}C{sup SP}e cm. Interpretation of the measurements are discussed. The results of similar calculations for {sup 133}Cs are d({sup 133}Cs)=124(4)d{sub e} or d({sup 133}Cs)=0.76(2)x10{sup -18}C{sup SP}e cm.
Dzuba, V. A.; Flambaum, V. V. [School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia)
Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet
A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A. F.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.
Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A.F.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.
Electric dipole response of He6: Halo-neutron and core excitations
Electric dipole (E1) response of He6 is studied with a fully microscopic six-body calculation. The wave functions for the ground and excited states are expressed as a superposition of explicitly correlated Gaussians. Final state interactions of three-body decay channels are explicitly taken into account. The ground state properties and the low-energy E1 strength are obtained consistently with observations. Two main peaks as well as several small peaks are found in the E1 strength function. The peak at the high-energy region indicates a typical macroscopic picture of the giant dipole resonance, the out-of-phase proton-neutron motion. The transition densities of the lower-lying peaks exhibit in-phase proton-neutron motion in the internal region, out-of-phase motion near the surface region, and spatially extended neutron oscillation, indicating a soft-dipole mode and its vibrationally excited mode. The compressional dipole strength is also examined in relation to the soft-dipole mode.
Mikami, D.; Horiuchi, W.; Suzuki, Y.
Experimental verification of isotropic radiation from a coherent dipole source via electric-field-driven LC resonator metamaterials.
It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator's gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present. PMID:24116780
Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, Andr�
Magnetic field penetration through protective metal screens using an equivalent magnetic dipole representation of an array of elliptical apertures
A model was developed to predict the coupling of external magnetic fields into a cylindrical object through an aperture shielded with a metal screen. Results from an experiment designed to test the model are presented. The coupling of these exterior fields through a single elliptical aperture is approximated by the radiation from an equivalent dipole into the object. The magnetic moments for this dipole are determined by the physical size of the aperture. The screen is then modeled as a linear superposition of many individual apertures. The total field at an interior point is calculated by summing the components of the fields from each of these apertures.
Richmond, Richard; O'Neal, James
Electric dipole (hyper)polarizabilities of spatially confined LiH molecule
In this study we report on the electronic contributions to the linear and nonlinear static electronic electric dipole properties, namely the dipole moment (?), the polarizability (?), and the first-hyperpolarizability (?), of spatially confined LiH molecule in its ground X 1?+ state. The finite-field technique is applied to estimate the corresponding energy and dipole moment derivatives with respect to external electric field. Various forms of confining potential, of either spherical or cylindrical symmetry, are included in the Hamiltonian in the form of one-electron operator. The computations are performed at several levels of approximation including the coupled-cluster methods as well as multi-configurational (full configuration interaction) and explicitly correlated Gaussian wavefunctions. The performance of Kohn-Sham density functional theory for the selected exchange-correlation functionals is also discussed. In general, the orbital compression effects lead to a substantial reduction in all the studied properties regardless of the symmetry of confining potential, however, the rate of this reduction varies depending on the type of applied potential. Only in the case of dipole moment under a cylindrical confinement a gradual increase of its magnitude is observed.
G�ra, Robert W.; Zale?ny, Robert; Koz?owska, Justyna; Naciap?ek, Paulina; Roztoczy?ska, Agnieszka; Strasburger, Krzysztof; Bartkowiak, Wojciech
Uncertainties of Modeling Gamma-ray Pulsar Light Curves Using Vacuum Dipole Magnetic Field
Current models of pulsar gamma-ray emission use the magnetic field of a rotating dipole in vacuum as a first approximation to the shape of a plasma-filled pulsar magnetosphere. In this paper, we revisit the question of gamma-ray light curve formation in pulsars in order to ascertain the robustness of the \\
Xue-Ning Bai; Anatoly Spitkovsky
Mechanical behaviour of a closed collar model for an 11.5 T dipole magnet.
A 10 cm long model of an 11.5 T Nb(sub 3)Sn accelerator dipole magnet, which will be built in the Netherlands, with a closed ring shaped collar has been constructed. Measurements of the collar deformation and the prestress at the poles have been made with...
W. Emden C. Daum J. Geerinck A. Ouden H. H. J. Kate
Rainbow singularities in the doubly differential cross section for scattering off a perturbed magnetic dipole
We take the scattering of electrons off a perturbed magnetic dipole as an example for demonstrating chaotic scattering systems with three open degrees of freedom. We explain the connection between the chaotic invariant set, the scattering functions and the doubly differential cross section. The most interesting structures in this cross section are curves of rainbow-type singularities. The ideal magnetic dipole has rotational symmetry; therefore, the dynamics has a conserved angular momentum, and the chaotic set of the three degrees of freedom system can be represented as a stack of chaotic sets of the reduced two degrees of freedom system where the numerical value of the conserved angular momentum serves as stack parameter. However, any real magnet deviates from a perfect dipole; therefore, we explain to which extent the qualitative properties of the cross section are robust against perturbations of the system, e.g., against deviations of the magnetic field from a perfect dipole which in general include the destruction of the rotational symmetry.
Gonzalez, F.; Jung, C.
Development of cos-theta Nb{sub 3}Sn dipole magnets for VLHC
This paper describes the double aperture dipole magnets developed for a VLHC based on Nb{sub 3}Sn superconductor, a cos-theta coil, cold and warm iron yokes, and the wind-and-react fabrication technique. Status of the model R and D program, strand and cable and other major component development are also discussed.
Alexander Zlobin et al.
Different Paths to Some Fundamental Physical Laws: Relativistic Polarization of a Moving Magnetic Dipole
In this paper we consider the relativistic polarization of a moving magnetic dipole and show that this effect can be understood via the relativistic generalization of Kirchhoff's first law to a moving closed circuit with a steady current. This approach allows us to better understand the law of relativistic transformation of four-current density�
Kholmetskii, Alexander L.; Yarman, T.
Novel Epoxy-Free Construction Method for Fabricating Dipole Magnets and Test Results.
Three model superconducting dipole magnets, lm length and having a bore diameter of 76mm, fabricated without epoxy resins or other adhesives, have been built and the first two have been tested in He I and He II. The conductor is the 23-strand Rutherford-t...
C. Taylor R. Althaus S. Caspi W. S. Gilbert W. Hassenzahl
Tune shift effect due to the sextupole longitudinal periodic structure in the superconducting dipole magnets
Using the standard Hamiltonian perturbation theory, the tune shift due to the sextupole periodic pattern in the superconducting dipole magnets is estimated for the Superconducting Super Collider (SSC) machine. The result indicates that this effect is of the order of 10{sup {minus} 9}. Therefore, this effect can be neglected in the dynamics of the beam.
Lopez, G.; Chen, S.
Using the standard Hamiltonian perturbation theory, the tune shift due to the sextupole periodic pattern in the superconducting dipole magnets is estimated for the Superconducting Super Collider (SSC) machine. The result indicates that this effect is of the order of 10[sup [minus] 9]. Therefore, this effect can be neglected in the dynamics of the beam.
Method of separating dipole magnetic anomaly from geomagnetic field and application in underwater vehicle localization
Because dipole magnetic anomaly caused by ferromagnetic object or geologic structural change is mixed with geomagnetic field and difficult to calculate its magnitude, it lead to a problem for automatic underwater vehicle (AUV) localization aided by geomagnetic anomaly. To solve this issue, a novel AUV localization method introducing draft depth is put forward, where vertical position of AUV relative to
Huang Yu; Hao Yan-ling
Alternate manufacturing processes and materials for the SSC dipole magnet coil end parts
Modern magnet designs such as the SSC dipole utilize smaller bore diameter and wider superconducting cable. Challenging winding techniques place greater emphasis on the role of the coil end parts. Their complex configuration is derived from their function of confining the conductors to a consistent given shape and location. Present end parts, made of G-10 composite, are manufactured utilizing complex
A. Lipski; R. Bossert; J. Brandt; J. Hoffman; G. Kobliska; J. Zweibohmer; W. Higinbotham; R. Shields; R. Sims
Charged spinning fluids with magnetic dipole moment in the Einstein-Cartan theory
A classical perfect charged spinning fluid with magnetic dipole moment in the Einstein-Cartan theory is described by using an Eulerian Lagrangian formalism. The field equations and equations of motion so obtained generalize those proposed by Ray and Smalley. We also clarify some open questions which appear in the works of Ray and Smalley and of de Ritis et al.
Amorim, R.
Relativistic turning acceleration of resonant electrons by coherent whistler mode waves in a dipole magnetic field
We report a very efficient process for accelerating high-energy electrons by coherent whistler mode waves in the Earth's dipole magnetic field, which we have found in our recent test particle simulations. The efficient acceleration process takes place for weakly relativistic seed electrons of a few hundred kiloelectronvolts. Under an assumption that the whistler mode wave packets are excited near the
Yoshiharu Omura; Naoki Furuya; Danny Summers
Measurements of field decay and snapback effect on Tevatron dipole magnets
The performance of Fermilab's Tevatron accelerator, currently in its Run II stage, is degraded by beam loss and emittance dilution during ramping from injection to collision energy. This could be related in part to insufficient compensation of dynamic effects such as the decay of the magnetic field in the dipoles during the dwell at injection and the following so-called snapback
Gueorgui V Velev; G. Annala; P. Bauer; R. Carcagno; J. DiMarco; H. Glass; R. Hanft; R. Kephart; M. Lamm; M. Martens; P. Schlabach; M. Tartaglia; J. Tompkins
Lymphocyte fractionation using immunomagnetic colloid and a dipole magnet flow cell sorter
The relationship between cell function and surface marker expression is a subject of active investigation in biology and medicine. These investigations require separating cells of a homogeneous subset into multiple fractions of varying marker expression. We have developed a novel cell sorter, the dipole magnet flow sorter (DMFS), which separates selected T lymphocyte subpopulations, targeted by immunomagnetic colloid, into multiple
Lee R. Moore; Maciej Zborowski; Liping Sun; Jeffrey J. Chalmers
Development of cos-theta Nb3Sn dipole magnets for VLHC
This paper describes the double aperture dipole magnets developed for a VLHC based on Nb3Sn superconductor, a cos-theta coil, cold and warm iron yokes, and the wind-and-react fabrication technique. Status of the model R&D program, strand and cable and other major component development are also discussed
Alexander Zlobin; G. Ambrosio; N. Andreev; E. Barzi; D. Chichili; V. V. Kashikhin; P. J. Limon; I. Terechkine; S. Yadav; R. Yamada
Production follow-up of the LHC main dipoles through magnetic measurements at room temperature
In this paper, we review the tools used for controlling the production of the LHC main dipoles through warm magnetic measurements. For the collared coil measurements, control limits are based on the statistics relative to the pre-series production. For the cold mass, the difference between collared coil and cold mass is considered, allowing a very stringent test. In both cases,
E. Wildner; S. Pauletta; Vittorio Remondino; Walter Scandale; Ezio Todesco; C. Vollinger
Spatial and field resolution of wire-wound fluxgates in magnetic dipole fields
We have enhanced the field and the spatial resolution of fluxgate magnetometers to measure magnetic dipole fields. With finite element simulations, we studied the flux distribution in the racetrack shaped core of a reference fluxgate magnetometer that was optimized for low noise performance in homogeneous fields. The influence of core length and thickness on the spatial and the field resolution
D. R�hmer; P. Shanmuganathan; F. Ludwig; M. Schilling
Cosmic Radiation in the Trapped Orbits of a Solar Magnetic Dipole Field
One of the well-known consequences which would follow from the existence of an appreciable solar magnetic dipole field is a diurnal variation in cosmic-ray intensity at intermediate latitudes on the earth. For the purpose of calculating the expected diurnal effect, it is first necessary to determine the extent to which the bounded orbits of the solar field are filled by
S. B. Treiman
Semiannual fluctuation depending on the polarity of the solar main magnetic dipole field
We examined the recently found semiannual fluctuation in the Sun-weather relations on a broader European region. The fluctuation means stronger solar effects on the weather in the spring and autumn periods than in summer or winter. The existence of this effect has been confirmed but only during the parallel orientations of the terrestrial and solar main magnetic dipole fields; this
T. Baranyi; A. Ludm�ny; G. Terdik
Observation of Chaotic Particle Transport Induced by Drift-Resonant Fluctuations in a Magnetic Dipole Field
The chaotic radial transport of energetic electrons trapped in a magnetic dipole field has been observed in a laboratory terrella. This transport is driven by multimode, drift-resonant plasma instabilities which are excited by the hot electron population. A transport simulation of energetic electrons interacting with a spectrum of electrostatic waves modeled on the measured fluctuations reproduces temporal features of the
H. P. Warren; M. E. Mauel
On the nonadiabatic theory of charged particles motion in the magnetic dipole field
The question of a nonadiabatic model of particle motion in the dipole field is considered. By applying the concepts of the leading line, the magnetic moment and the loss cone, an analogy to traditional ideas of the adiabatic motion theory for trapped particles of high energy is determined through numerical experiment.
I. V. Amirkhanov; E. P. Zhidkov; A. N. Ilina; V. D. Ilin; B. Yu. Yushkov
Scattering of a plane gravitational wave by a magnetic dipole field in the Schwarzschild metric
The equations governing the propagation of high-frequency coupled gravitational and electromagnetic waves are integrated for the case of a plane gravitational wave impinging onto a Schwarzschild space-time equipped with a magnetic dipole field. The generated electromagnetic wave is focused due to the gravitational lens effect. An expression is derived for the intensity of the electromagnetic wave in the focal region.
T. Elster
A Study of the Magnetic Dipole Field of LEP during the 1995 Energy Scan
In preparation for the 1995 LEP energy scan additional instrumentation was installed in two tunnel dipoles to monitor the time evolution of the magnetic field during experimental fills. Significant increase of the bending field superimposed by day-time dependent fluctuations on a minute time scale were revealed. These unexpected features could be correlated with earth currents captured by the LEP vacuum
Bernd Dehning; A Drees; M A Geitz
The periodicity of a charged particle motion in a magnetic dipole field
The author's purpose is to present in this article the evidence of his intuition on the periodic behavior of a charged particle, moving in a magnetic dipole field, that is achieved by adopting the Alfv�n's analysis of the motion into the composite of two motions and studying the contribution of these motions into the general behavior of the charged particle,
A. G. Mavraganis
Experimental results on the space charge compensation of ion beams in a magnetic dipole field
The space charge potential of a positively charged ion beam traversing a magnetic dipole field has been measured with a modified Langmuir probe. The measurements were carried out in the homogeneous field region as well as in the fringe field using dc ion beams of the elements He, Ne, Ar and Kr in the energy range between 30 and 45
R. M. Hausner; H. Baumann; K. Bethge
Two modes of the motion of charged particles in the magnetic dipole field
Based on Stormer's equations for a magnetic dipole, the author considers two different modes of the motion of charged particles - the gyrorotation mode and the mode with slowly changing phase. Differential equations for the longitudinal velocity of particles which describe both modes are derived. The criterion of transition from one mode to the other obtained from the law of
S. F. Nosov
The Periodicity of a Charged Particle Motion in a Magnetic Dipole Field
Direct problem of calculating the magnetic dipole field in a quasilayered medium
A method is developed for calculating the electromagnetic field of a magnetic dipole in a quasilayered two-dimensional medium.\\u000a The quasi-three-dimensional problem is reduced to a two-dimensional problem for the Fourier-transformed electromagnetic field.\\u000a An equivalent system of integral equations on the layer boundaries is obtained.
V. I. Dmitriev; A. N. Silkin
Magnetic dipole moment estimates for an ancient lunar dynamo
The four measured planetary magnetic moments combined with a recent theoretical prediction for dynamo magnetic fields suggests that no dynamo exists in the moon's interior today. For the moon to have had a magnetic moment in the past of sufficient strength to account for at least some of the lunar rock magnetism, the rotation would have been about twenty times faster than it is today and the radius of the fluid, conducting core must have been about 750 km. The argument depends on the validity of the Busse solution to the validity of the MHD problem of planetary dynamos.
Anderson, K. A.
Brief Electricity and Magnetism Assessment
The Brief Electricity and Magnetism Assessment (BEMA), developed by Chabay and Sherwood, assesses student understanding of basic electricity and magnetism concepts. It is written for college-level calculus-based introductory physics courses. The files are password protected; users who wish to access the assessment will need to contact the authors. A Spanish translation of BEMA is available under Supplemental Documents. The reliability and discriminatory power of this assessment tool have been tested. The results are available at: Physical Review Special Topics - Physics Education Research: Volume 2, Issue 1, Page 7, http://prst-per.aps.org/abstract/PRSTPER/v2/i1/e010105
Physics Topics: Electricity and Magnetism
This item is a section of an introductory physics textbook. It provides content support on electrostatics, electric field and potential, current electricity, magnetic field and force, and electromagnetic phenomena. The author, a veteran professor of physics, has summarized his own notes from "lectures that worked" and blended them with calculus-based practice problems with solutions. It is designed to supplement teachers and learners who have mastered basic concepts but need support with calculus-based operations and differential equations.
Tatum, J. B.
Electric dipole moments of charged leptons and lepton flavor violating interactions in the general two Higgs doublet model
We calculate the electric dipole moment of the electron using the experimental result of the muon electric dipole moment and upper limit of the BR(?-->e?) in the framework of the general two Higgs doublet model. Our prediction is 10-32 e cm, which lies in the experimental current limits. Further, we obtain constraints for the Yukawa couplings ?�DN,?e and ?�DN,??. Finally, we present an expression which connects the BR(?-->??) and the electric dipole moment of the ? lepton and study the relation between these physical quantities.
Quench problems of Nb3 Sn cosine theta high field dipole model magnets
We have developed and tested several cosine theta high field dipole model magnets for accelerator application, utilizing NbSn strands made by MJR method and PIT method. With Rutherford cables made with PIT strand we achieved 10.1 Tesla central field at 2.2 K operation, and 9.5 Tesla at 4.5 K operation. The magnet wound with the MJR cable prematurely quenched at
Ryuji Yamada; Masayoshi Wake
Quench problems of Nb3Sn cosine theta high field dipole model magnets
We have developed and tested several cosine theta high field dipole model magnets for accelerator application, utilizing Nb3Sn strands made by MJR method and PIT method. With Rutherford cables made with PIT strand we achieved 10.1 Tesla central field at 2.2 K operation, and 9.5 Tesla at 4.5 K operation. The magnet wound with the MJR cable prematurely quenched at
An experimental 11.5 T Nb3Sn LHC type of dipole magnet
As part of the magnet development program for the LHC an experimental 1 m long 11.5 T single aperture Nb3Sn dipole magnet has been designed and is now under construction. The design is focused on full utilisation of the high current density in the powder tube Nb3Sn. A new field optimisation has led to a different winding layout and cable
A. den Ouden; S. Wessel; E. Krooshoop; R. Dubbeldam; H. H. J. ten Kate
Corrector magnets: Combined structural analysis of collier 50 mm aperture ordered wound dipoles interior section
The 50mm aperture prototype collider ordered wound dipole connector magnets have been modeled with finite element techniques considering the individual and combined load cases of the preloading from keys, cooldown to 4 K and the effect of magnetic forces during energizing. Results of the analysis are presented as longitudinal, transverse and shear stresses for the ordered wound coils and as maximum von Mises stress for the carbon steel outer laminations, the stainless steel inner lamination, and the carbon steel keys.
Tran, Vu H.
Design and development of Nb3Sn single-layer common coil dipole magnet for VLHC
Common coil dipole magnets based on Nb3Sn conductor and the react-and-wind technology are a promising option for the next generation of hadron colliders. The react-and-wind technology has potential cost benefits related to less expensive cable insulation, structural materials and magnet fabrication. A common coil design allows the use of a pre-reacted Nb3Sn superconductor with low critical current degradation after bending.
Giorgio Ambrosio; N. Andreev; E. Barzi; P. Bauer; D. Chichili; K. Ewald; S. Feher; L. Imbasciati; V. V. Kashikhin; S. W. Kim; P. Limon; I. Novitski; J. M. Rey; S. Yadav; R. Yamada; A. V. Zlobin; R. Scanlan
The results of design and tests of 2T superconducting model dipoles, operating at 1Hz, are presented. The magnets use a SC coil made from hollow superconducting cable, cooled with forced flow two-phase helium, and utilise a two section window frame iron yoke at different temperatures: one section at 4.5 K, the other at 80 K. Measurements of magnet training, AC
A. Kovalenko; N. Agapov; S. Averichev; A. Doniagin; I. Eliseeva; I. Karpunina; H. Khodzhibagiyan; V. Kuzichev; G. Kuznetsov; A. Nesterov; P. Nikitaev; A. Starikov; L. Zaitsev; C. Muehle; E. Fischer; G. Hess; J. Kaugerts; M. Kauschke
Test results of RD3c, a Nb3Sn common-coil racetrack dipole magnet
The superconducting magnet group at Lawrence Berkeley National Laboratory has been developing racetrack coil technology for economical, high-field accelerator magnets from brittle superconductor. Recent tests have demonstrated 1) robust, reusable, double-layer, flat racetrack, wind and react Nb3Sn coils, 2) a reusable, easily assembled coil-support structure that can minimize conductor movement and 3) nearly 15 T dipole fields, without conductor degradation.
A. F. Lietzke; S. Caspi; L. Chiesa; M. Coccoli; D. R. Dietderich; P. Ferracin; S. A. Gourlay; R. R. Hafalia; A. D. McInturff; G. Sabbi; R. M. Scanlan
Information content of the low-energy electric dipole strength: Correlation analysis
Background: Recent experiments on the electric dipole (E1) polarizability in heavy nuclei have stimulated theoretical interest in the low-energy electric dipole strength, both isovector and isoscalar.Purpose: We study the information content carried by the electric dipole strength with respect to isovector and isoscalar indicators characterizing bulk nuclear matter and finite nuclei. To separate isoscalar and isovector modes, and low-energy strength and giant resonances, we analyze the E1 strength as a function of the excitation energy E and momentum transfer q.Methods: We use the self-consistent nuclear density functional theory with Skyrme energy density functionals, augmented by the random phase approximation, to compute the E1 strength and covariance analysis to assess correlations between observables. Calculations are performed for the spherical, doubly magic nuclei 208Pb and 132Sn.Results: We demonstrate that E1 transition densities in the low-energy region below the giant dipole resonance exhibit appreciable state dependence and multinodal structures, which are fingerprints of weak collectivity. The correlation between the accumulated low-energy strength and the symmetry energy is weak, and dramatically depends on the energy cutoff assumed. On the other hand, a strong correlation is predicted between isovector indicators and the accumulated isovector strength at E around 20 MeV and momentum transfer q�0.65 fm-1.Conclusions: Momentum- and coordinate-space patterns of the low-energy dipole modes indicate a strong fragmentation into individual particle-hole excitations. The global measure of low-energy dipole strength correlates poorly with the nuclear symmetry energy and other isovector characteristics. Consequently, our results do not support the suggestion that there exists a collective �pygmy dipole resonance,� which is a strong indicator of nuclear isovector properties. By considering nonzero values of momentum transfer, one can isolate individual excitations and nicely separate low-energy excitations from the T=1 and T=0 giant collective modes. That is, measurements at q>0 may serve as a tool to correlate the E1 strength with certain bulk observables, such as incompressibility and symmetry energy.
Reinhard, P.-G.; Nazarewicz, W.
Exact Solution of the Mean Spherical Model for Fluids of Hard Spheres with Permanent Electric Dipole Moments
The mean spherical model is solved in closed form for a fluid of hard spheres with permanent electric dipole moments. Both the pair distribution function g(12) and the direct correlation function c(12) consist of a spherically symmetric term and two other terms with different dependences on the orientations of the two dipole moments. The spherically symmetric part is the solution
M. S. Wertheim
Magnetic field angle changes during manufacture and testing of SSC collider dipoles
Measurements of the magnetic field angle along the length of collider dipole magnets are discussed. These superconducting magnets were built at Fermilab for the Superconducting Super Collider (SSC) by Fermilab and General Dynamics personnel. These measurements were made at four stages in the assembly and test sequence. The data show-that changes can occur both during installation in the cryostat and as a result of cold testing. Most of the changes during installation are correlated with the welding of the tie bar restraints. But the changes observed as a result of the cold testing can be attributed to changes in the magnetization of the iron laminations.
Kuchnir, M.; Bleadon, M.; Delchamps, S.W.; Schmidt, E.; Bossert, R.; Carson, J.; Gourlay, S.; Hanft, R.; Koska, W.; Lamm, M.J.; Mazur, P.O.; Orris, D.; Ozelis, J.; Strait, J.; Wake, M. [Fermi National Accelerator Lab., Batavia, IL (United States); Devred, A.; DiMarco, J.; Kuzminski, J.; Ogitsu, T.; Yu, Y.; Zheng, H. [Superconducting Super Collider Lab., Dallas, TX (United States)
Large tau and tau neutrino electric dipole moments in models with vectorlike multiplets
It is shown that the electric dipole moment of the {tau} lepton several orders of magnitude larger than predicted by the standard model can be generated from mixings in models with vectorlike mutiplets. The electric dipole moment (EDM) of the {tau} lepton arises from loops involving the exchange of the W, the charginos, the neutralinos, the sleptons, the mirror leptons, and the mirror sleptons. The EDM of the Dirac {tau} neutrino is also computed from loops involving the exchange of the W, the charginos, the mirror leptons, and the mirror sleptons. A numerical analysis is presented, and it is shown that the EDMs of the {tau} lepton and the {tau} neutrino which lie just a couple of orders of magnitude below the sensitivity of the current experiment can be achieved. Thus the predictions of the model are testable in an improved experiment on the EDM of the {tau} and the {tau} neutrino.
Ibrahim, Tarek [Department of Physics, Faculty of Science, University of Alexandria, Alexandria (Egypt); Department of Physics, Northeastern University, Boston, Massachusetts 02115-5000 (United States); Nath, Pran [Department of Physics, Northeastern University, Boston, Massachusetts 02115-5000 (United States)
Probing CP Violation with the Electric Dipole Moment of Atomic Mercury
The electric dipole moment of atomic {sup 199}Hg induced by the nuclear Schiff moment and the tensor-pseudotensor electron-nucleus interactions are calculated. For this, we