strength of the optical nonlinearity, and I is the Gaussian intensity profile of the beam. The phenomenon of self-focusing may occur if a beam of light with nonuniform transverse intensity distribution, for example Gaussian profile, propagates through a material in which n2 is positive. If a strong beam of light passes through a medium with this type of nonlinearity also called Kerr nonlinearity, then the refractive index of the medium inside the beam is greater than that outside of the beam. If the electric field is strong enough then the beam will create a dielectric waveguide, which reduces or entirely eliminates the divergence of the beam. Askaryan called this effect self-focusing. Discovery of self-focusing opened a new chapter in non-linear electrodynamics and optics. Askaryan effect The Askaryan effect, which was theoretically predicted by Askaryan in 1962, describes a phenomenon, similar to the Cherenkov effect, whereby a particle travelling faster than the speed of light in a dense radiotransparent medium such as salt, ice or the lunar regolith produces a shower of secondary charged particles which contain a charge anisotropy and thus emits a cone of coherent radiation in the radio or microwave part of the electromagnetic spectrum. This phenomenon is of primary interest in using bulk matter to detect ultra-high energy neutrinos. Other Askaryan was the first to note that the outer few metres of the Moon's surface, known as the regolith, would be a sufficiently transparent medium for detecting microwaves from the charge excess in particle showers. The radio transparency of the regolith has since been confirmed by the Apollo missions. Askaryan also found (together with M. L. Levin) a combination of auxiliary high-frequency elds which could secure stability of electron bunch during acceleration. Selected works Source: ISI Web of Knowledge Askaryan GA, 'O GENERATSII RADIOVOLN MILLIMETROVOGO DIAPAZONA PRI PROKHOZHDENII ELEKTRONNOGO SGUSTKA CHEREZ TORMOZYASHCHUYU SREDU', ZHURNAL EKSPERIMENTALNOI I TEORETICHESKOI FIZIKI 27 (6): 761-761 1954 Askaryan GA, 'ACCELERATION OF CHARGED PARTICLES IN RUNNING OR STANDING ELECTROMAGNETIC WAVES', SOVIET PHYSICS JETP-USSR 9 (2): 430-430 1959 Askaryan GA, 'RADIATION OF VOLUME AND SURFACE COMPRESSION WAVES DURING IMPINGEMENT OF A NONRELATIVISTIC ELECTRON STREAM AT THE SURFACE OF A DENSE MEDIUM', SOVIET PHYSICS-TECHNICAL PHYSICS 4 (2): 234-235 1959 Askaryan GA, 'ELECTROMAGNETIC RADIATION FROM ELECTRON DIFFUSION', SOVIET PHYSICS JETP-USSR 12 (1): 151-152 1961 Askaryan GA, 'DIAMAGNETIC PERTURBATIONS IN MEDIA CAUSED BY IONIZING RADIATION', SOVIET PHYSICS JETP-USSR 14 (1): 135-137 1962 Askaryan GA,'INTERACTION BETWEEN LASER RADIATION