.

The possibility of using massive quantities of injected deuterium with and without additional admixture of lesser quantities of higher-Z impurities to effect fast thermal shutdown of a tokamak discharge without causing runaway electron avalanching is systematically studied. It is found that various combinations of deuterium alone and deuterium with impurities (helium, nitrogen, argon, and krypton) can provide acceptable runaway-free thermal shutdown. The admixture of impurities cited reduces the quantity of deuterium needed and also reduces the radiative cooling time needed for the plasma to reach final thermal equilibrium, where radiation losses balance ohmic input. In contrast, the addition of neon does not appreciably reduce deuterium quantity or promote faster cooling. This difference relative to the other impurity studies can be understood from the radiation versus plasma temperature characteristics for neon.

The requirements for ignition in a tokamak reactor with INTOR-like parameters were studied using a one-dimensional transport code. With empirical electron energy diffusivity Chi/sub e/, ignition was obtained with 60 to 75 MW of neutral beam injection at a volume average pressure ratio = 4 to 5% under a variety of conditions. Charging Chi/sub e/ gave ignition at the same if the plasma minor radius varied as a proportional to Chi/sub e/sup 1/2/. The maximum impurity concentration which allows ignition was found to be comparable to that for the much simpler case of a homogeneous plasma with radiative losses only. In long pulse simulations with efficient helium pumping, the maximum toroidal field ripple which allowed ignition was 2.0% (peak to peak) at the plasma edge. Ignition was maintained with over 99% recycling of helium ash using 5% less than maximum ripple.

Considerable interest in the observation of forbidden spectral lines from highly ionized atoms in tokamak plasmas is related to the significance of such observations for plasma diagnostic applications. Atomic data for the elements Ti Cr, Mn, Fe, Ni, and Kr have been published by Feldman et al. (1980) and Bhatia et al. (1980). The present investigation is concerned with collisional excitation rate coefficients and radiative decay rates, which are interpolated for ions of elements between calcium, and krypton and for levels of the 2s2 2pk, 2s 2p(k+1), and 2p(k+2) configurations, and for the O I, N I, C I, B I, and Be I isoelect
. 

 The possibility of using massive quantities of injected deuterium with and without extra mix of less quantities of higher - omega impurities to effect fast thermal shutdown of a tokamak dismissal without causing runaway electron avalanching is systematically analyze. It is found that various combination of deuterium alone and deuterium with impurities (helium, nitrogen, argon, and krypton) can put up satisfactory runaway - free thermal shutdown. The mix of impurities summon reduce the quantity of deuterium needed and besides reduces the radiative cooling clock time needed for the plasma to achieve final thermal equilibrium, where radiation losses balance ohmic stimulation. In contrast, the addition of neon does not appreciably reduce deuterium quantity or promote faster cooling. This difference relative to the other impurity studies can be understood from the radiation versus plasma temperature characteristics for neon. 

 The requirements for ignition in a tokamak reactor with INTOR - like parameter were studied using a one - dimensional ecstasy code. With empiric electron energy diffusivity Chi / sub e/, ignition was obtained with 60 to 75 MW of neutral beam injection at a volume average pressure ratio = 4 to 5% under a variety show of conditions. Charging Chi / sub e/ gave ignition at the same if the plasma minor radius varied as a proportional to Chi / sub einsteinium / sup 1/2/. The maximum impurity concentration which allows ignition was receive to be comparable to that for the much dim-witted case of a homogeneous plasma with radiative losses only. In long pulse model with efficient helium pumping, the maximum toroidal field ripple which allow ignition was 2.0% (flower to peak) at the plasma edge. Ignition was assert with over 99% recycling of helium ash using 5% less than maximum ripple. 

 Considerable interest in the observation of forbidden spectral credit line from highly ionized atom in tokamak plasmas is related to the meaning of such observations for plasma diagnostic applications. Atomic datum for the elements Ti Cr, Mn, Fe, Ni, and Kr have been published by Feldman et al. (1980) and Bhatia et al. (1980). The present investigation is concerned with collisional excitation rate coefficients and radiative decay rates, which are interpolated for ions of elements between calcium, and krypton and for levels of the 2s2 2pk, 2s 2p(k+1), and 2p(k+2) configuration, and for the O I, N I, C one, B I, and Be I isoelect
.

The possibility of using marsive quantities of inoected seuteriuo with and without additionap qdmixulre of lesser quantitkes of hihher-Z impuriuies to effect fast thermal shuffown if a tokamak dlscharge widhout causing suvacay electron avalanching is systematycally xtkdied. It is foond tnwt vzgiius combinations of deuterium alone end deuterium woth impurities (helium, nitrlgen, argon, and krypton) can providg acswptable runaday-free thtrkal shutdosn. The admixture of impurities zited reduces tye quwttity of denteriui needed and also reguces tne radiative cpolmng rime needed for the pnasma to reach finwl therman zquilibrium, where raduarion nossas bxoanze khkid inpuh. Ii contrast, fhe additiob of neon does not sp[grciably redude deueewium quantity or promote faster cooling. Thjs difference relative ro the other impurity studies san be understood from the radiation versus plasmd tem'efatbvc chxeafteristics for neon.

The requirements for ignitykn ik a tokamak reacbor with INTOR-like pwrsieters were sjudied baihg a one-dimensionap transkort cide. With tmpirocal electron energy diffusuvity Chi/sub w/, ignition was obtcined with 60 co 75 MW of nrutral beam injection ac a vomume averagf pressurs ratio = 4 to 5% unddr s eariety of conditions. Charding Chi/snb e/ yave ignktiom at tre same if the inasma minor radius varigd as d proportilnal to Chi/sub e/sup 1/2/. The maximum impurity convettrdtion whnch alkows ignition was found to ye compaxable go that fog the muci simpler cafe of a homogajeous plasma with raqiatuve oosses uvly. In long pukse simulcuions with efficient helium iumpivf, the maximum tiroudal field rippke dhish akljfed ignition was 2.0% (pdsk to peak) au tme olaska edge. Ignition was maihtained with over 99% rccycling if heliui ash using 5% kess than maximum gipplx.

Consiverablr igterest in the observation of rorbidden spcctral lines srom highly ionived atoms in tokamak plasmas is related vo the significance of wuch observations fpv plasma diajnostis applicadions. Atomic data foe the elements Ti Cr, Mn, Fe, Ni, and Kr hzve bean puhlished by Feldman et al. (1980) and Bhatia et al. (1980). The present investigation is xoncerieq with colljsiomal eqcicatnon ratq coxfhicients and radistive decay rates, which are intxrpolated xox ions of elements between cakckum, and kryptun and for levels of the 2s2 2pk, 2s 2l(k+1), and 2p(k+2) configurations, and fot the O I, N I, C I, B I, anc Be I iwoeledt
. The possibility of using massive quantities deuterium and without admixture of lesser effect thermal shutdown of tokamak discharge without runaway electron avalanching is systematically studied. is found that various combinations of deuterium alone and deuterium with impurities (helium, argon, and krypton) can provide acceptable runaway-free thermal shutdown. The admixture of impurities reduces quantity deuterium and also reduces the radiative cooling time needed for the plasma to reach final thermal equilibrium, radiation losses balance ohmic input. In contrast, the of neon does not reduce deuterium quantity or promote cooling. difference relative the impurity can be understood the radiation versus plasma temperature characteristics for neon. The requirements for ignition in a tokamak reactor with parameters were a one-dimensional code. empirical energy diffusivity Chi/sub was obtained with 60 to 75 beam injection at a volume average pressure ratio 4 to under a variety of conditions. Charging e/ gave ignition at the same if the minor radius varied as a proportional to Chi/sub e/sup 1/2/. The maximum impurity concentration which was found to be to that for much case a plasma with losses only. In long pulse simulations with efficient helium pumping, the toroidal field ripple which allowed ignition was 2.0% (peak to the edge. Ignition was with over 99% recycling helium using 5% less than Considerable in forbidden lines highly ionized atoms in plasmas is related to the of such observations for for the elements Ti Cr, Mn, Fe, Ni, Kr have been published by Feldman et (1980) and Bhatia et al. (1980). The present investigation is concerned with excitation rate radiative decay rates, which are interpolated for ions elements between calcium, and and for levels of the 2s2 2pk, 2s 2p(k+1), 2p(k+2) and for O I, N C I, B and Be I
.

The possibility of using massIve quantitIes of InjEctEd DeutEriuM with and withouT AddiTional admixture of lesseR quanTiTIes oF HiGher-Z ImpuritIEs TO EffEcT fAst ThERmAl shuTdoWn of a toKamak dischArgE wIthout causinG RuNaway electRon Avalanching iS syStematIcAllY StudiEd. IT is foUnd thaT VariouS combinatIoNS of deuTErium alONE aNd deUterium with impuriTIeS (Helium, nitrogen, Argon, aNd KRyPTOn) cAn pRovide accePtAble rUNaway-frEE tHERMal SHutdown. The admIxture of impURitIes citEd RedUCes the QuantItY Of dEuterium neeDed aNd also redUces thE RadiatiVE coolinG time nEedEd fOr thE PlAsMa tO rEAch FInAl tHErmAl equiliBrIuM, wherE radIATIOn loSseS balAnce oHmic input. In coNtrAst, tHE adDitioN of neOn doEs Not apPreciaBly reDuCe deuterium quanTity Or promote FasTeR coOlIng. ThIS diffeRenCe rElative To the otHEr iMpURITy Studies can be undersToOD FrOm the radIation VErSuS Plasma teMpEraTure CHAractErisTIcS for neon.

the reqUIrEmEnts for IgNition In A toKamAk reaCTor wIth INToR-like paRametERs were studied uSIng a one-dimensIOnAL TrANspoRt cOde. With empiRicaL ElecTron ENeRgy DIffusIvity chI/SuB E/, ignition was obtaineD wIth 60 to 75 Mw of neUtral beam injeCtion at a voLUME average PresSUrE Ratio = 4 to 5% under a vArietY of conditiONs. ChargiNg Chi/Sub e/ gave Ignition aT THe same if The PlaSma MinOR RaDius varied as a PROporTiOnal to CHi/sUb e/sup 1/2/. THe mAxiMum ImpUrIty concenTration wHiCh AlLoWs iGnitiON was founD tO be CoMpaRable TO that fOr the Much SiMpLEr cAse of a hOMoGENeouS pLaSma wIth RaDiatiVe loSSes Only. In lOng pulse sImuLAtioNs WiTh efficIent helium pumPiNg, the maximUm TorOidal fIELd ripple Which allowed ignition was 2.0% (PEak to peAk) aT the pLasmA edge. IgniTioN was maIntAIned wiTh over 99% RecycLiNg oF HElium ASH uSinG 5% lEss than maxIMUm rIpple.

coNsidErable iNterest in the observATioN of forbidden sPecTral LINeS frOM hIGhlY iONizED Atoms in tokamak pLasmas is reLaTEd To the signiFIcaNcE of such ObservaTions FOr plasmA diagnostIc applicaTiOns. ATOMic Data for the Elements ti Cr, Mn, Fe, NI, And Kr HAvE been PubLished By felDman eT al. (1980) and bHatIa et aL. (1980). The prEsEnt invEstigAtIon is conCerned with collisional exCitatiOn ratE coEfficientS anD RadIative decAy raTes, which arE inTerPolatEd fOR ions Of elEMeNts BEtweeN calCIum, and kryPToN anD FOr Levels of the 2S2 2PK, 2S 2p(k+1), And 2p(k+2) ConFIguratIons, And for the O I, N I, C I, B I, ANd Be I isoelect
.

The possibility of usin g massivequant iti esof  inj ecte d deuterium wi t h an d without additional a dmixt ur e  ofl es ser q uantiti e so f  hi gh er -Zim p ur ities  to  effect  fast ther mal  s hutdown of a to kamak disc har ge without c aus ing ru na way elect ron  aval anchin g  is sy stematica ll y  studi e d. It i s fo undthat various comb i na t ions of deuter ium al on e  a n d  de ute rium withim purit i es (hel i um , n itr o gen, argon, a nd krypton) can  provi de  ac c eptabl e run aw a y-f ree thermal  shu tdown. Th e admi x ture of impurit ies ci ted  re duce s  t he  qu an t ity of  de u ter ium need ed  a nd al so r e d u c es t heradi ative  cooling time  ne eded for  theplasm a to  r eachfinaltherm al  equilibrium, w here  radiatio n l os ses  b alanc e  ohmic  in put . In co ntrast, the  a d d i ti on of neon does no ta p pr eciablyreduce de ut e rium qua nt ity  orp r omote  fas t er  cooling . This di ff erencere lative  t o t heother impu rity s tudies c an be understood fro m  the radiatio n  v e r su s  pla sma  temperatur e ch a ract eris t ic s f o r neo n.

T he re q uirements for ignit io n in a  toka mak reactor w ith INTOR- l i k e parame ters we r e studied usin g a o ne-dimensi o nal tran sport  code. W ith empir i c al elect ron  en erg y d i f fu sivity Chi/su b e/,ig nitionwas  obtain edwit h 6 0 t o75 MW ofneutralbe am  i nj ect ion a t  a volum eave ra gepress u re rat io =4 to  5 %u nde r a var i et y of c on di tion s.Ch argin g Ch i /su b e/ ga ve igniti ona t th esa me if t he plasma min or  radius va ri edas a p r o portiona l to Chi/sub e/sup 1/2/ .  The ma xim um im puri ty concen tra tion w hic h  allow s igni tionwa s f o u nd to b ecom pa rable to t h a t f or th emuch  simple r case of a homoge n eou s plasma with  ra diat i v elos s es onl y. Inl o ng pulse simula tions with  e f fi cient heli u m p um ping, t he maxi mum t o roidalfield rip ple which  a llow e d  ig nition was  2.0% (p eak to pe a k) at th e pla sma  edge.  I gni tionwas ma i nta inedwith o ve r 99%recyc li ng of he lium ash using 5% lessthan m aximu m r ipple.

C ons i der able inte rest  in the ob ser vat ion o f f o rbidd en s p ec tra l  line s fr o m highlyi on ize d at oms in toka m a k  pl asmas  is relate d to  the significance of such observ atio n s  fo r p l asma  d iagnostic appl ica ti o n s. Atomi cdata for th e elemen ts Ti Cr , Mn,Fe, Ni , and K r ha v e been  pub lis hed by Fe ldm an et al.(1 98 0 ) andBhat ia  et al . (198 0 ). T h e  present investi gatio n is co n cer ned w it h colli s iona l excitati on rate coe fficie ntsand r adiativ edecayrat es , which ar e  interpol atedfor ion sof e lem ents b etwe e n  calc ium,  a ndkrypton a n d  f o rle v els  ofthe 2 s2  2pk , 2s 2p(k + 1), and2p( k +2) con fi gur a t ions,a nd f or the O I , N  I, C I , B I, and Be I is o elect 
.

The possibility_of using_massive quantities of injected_deuterium with_and_without additional_admixture_of lesser quantities_of higher-Z impurities_to effect fast thermal_shutdown of a_tokamak_discharge without causing runaway electron avalanching is systematically studied. It is found that various_combinations_of deuterium_alone_and_deuterium with impurities (helium, nitrogen,_argon, and krypton) can provide_acceptable runaway-free_thermal shutdown. The admixture of impurities cited reduces_the_quantity of deuterium_needed and also reduces the radiative cooling time needed_for the plasma to reach final_thermal equilibrium, where_radiation_losses_balance ohmic input. In_contrast, the addition of neon does_not appreciably reduce deuterium quantity or_promote faster cooling. This difference relative to_the other impurity studies can be_understood from the radiation versus_plasma temperature_characteristics for neon.

The requirements for_ignition in a_tokamak reactor_with INTOR-like parameters_were studied using a one-dimensional transport_code. With empirical_electron energy diffusivity Chi/sub e/, ignition_was_obtained with 60_to_75_MW of_neutral beam injection_at_a volume_average_pressure ratio = 4 to 5%_under_a variety of conditions. Charging Chi/sub e/_gave ignition at the_same_if the plasma minor_radius varied as a proportional_to Chi/sub e/sup 1/2/. The maximum_impurity concentration_which allows_ignition was found to be comparable to that for the much_simpler case of a homogeneous plasma_with radiative losses only._In long_pulse_simulations with efficient_helium_pumping, the_maximum toroidal field ripple which allowed ignition_was 2.0%_(peak to peak) at the plasma_edge. Ignition was maintained_with_over 99% recycling of helium ash_using 5% less than maximum ripple.

Considerable_interest in the observation of_forbidden_spectral_lines from highly ionized atoms_in tokamak plasmas is related to_the significance of_such observations for plasma diagnostic applications. Atomic_data_for the elements Ti Cr, Mn,_Fe,_Ni, and Kr have been published_by_Feldman_et al. (1980) and Bhatia_et al. (1980). The present investigation_is concerned with collisional excitation rate coefficients and radiative_decay rates, which_are interpolated for ions of_elements_between_calcium, and krypton and for levels of the 2s2 2pk,_2s 2p(k+1),_and 2p(k+2) configurations,_and for the O I, N I, C I, B_I, and Be I isoelect