Gurgen Askaryan

Gurgen Ashotovich Askaryan (Armenian: Գուրգեն Ասկարյան; Russian: Гурген Аскарьян or Гурген Аскарян) (14 December 1928 – 2 March 1997) was a prominent Soviet - Armenian physicist, famous for his discovery of the self-focusing of light, pioneering studies of light-matter interactions, and the discovery and investigation of the interaction of high-energy particles with condensed matter.

For his famous discovery of the self-focusing of light, he received the highest scientific award at the time in the Soviet Union.

This energy loss is transformed into heat in amount which is sufficient to induce boiling along particle's trajectory.

G. Askaryan discovered and investigated in details various effects accompanying passage of high energy particles through dense matter (liquids or solids).

Askaryan's results made it possible to detect showers and single particles using sound receivers situated at some distance from the event.

Several years ago, the registration of energetic particles and showers with sound detectors in sea water was planned as an important part of global monitoring.

G. Askaryan also showed that cosmic ray showers emit electromagnetic radiation, thus giving yet another way for their detection.

[2] Before him it was commonly assumed that electron-photon showers do not emit electromagnetic radiation since the electrons and positrons are created in pairs.

Later G. Askaryan showed that intense laser beam passing through matter also generates sound waves.

As a result of this series of investigations, a new branch of physics was created, radiation acoustics, and G. Askaryan was the founder.

Vaporizing ablation is now used for compressing the nuclear fuel in the problem of laser induced controlled thermonuclear reactions.

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.

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.

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.

[7] Askaryan also found (together with M. L. Levin) a combination of auxiliary high-frequency elds which could secure stability of electron bunch during acceleration.

Source: ISI Web of Knowledge Note: The article is based on the biographical paper about Gurgen Askaryan written by his friend and colleague Boris Bolotovskii.