Andrei Viktorovich Gaponov-Grekhov (born 7.06.1926) is a Soviet physicist and an academician (1968; corresponding member 1964). He was born in Moscow. He graduated from Gorky University (1949). In 1952 — 55 he worked at the Gorky Polytechnic Institute, from 1955 he was head of a department and then deputy director of the Radiophysical Research Institute, and since 1977 he has been director of the Institute of Applied Physics of the USSR Academy of Sciences (Gorky).
His research is in the field of microwave electrodynamics and electronics, high-power electronics, plasma physics, nonlinear optics, the physics of millimetre and submillimetre wavelengths, the theory of nonlinear wave processes, the theory of oscillations and analytical dynamics. He laid the foundations of a general analytical theory of electrical machines. He formulated (1959) the idea that induced radiation can arise in a beam of excited non-isochronous oscillators, and on this basis powerful generators of electromagnetic oscillations in the millimetre and submillimetre ranges were developed, using open resonators and special cryomagnetic systems to produce strong magnetic fields (gyrotrons). He solved a number of problems connected with the particular features of the interaction of relativistic electron beams with electromagnetic waves, and drew up recommendations for the creation of various generators of pulses of powerful coherent microwave radiation. For his theoretical and experimental study of induced cyclotron radiation, on the basis of which cyclotron-resonance masers were created, he was awarded the USSR State Prize in 1967.
He formulated proposals for the confinement and the acceleration of plasma by high-frequency fields. Together with M. A. Miller he introduced the concept of the high-frequency potential, which made it possible to write down simple equations describing the dynamics of nonlinear electromagnetic phenomena in plasma. He is studying the interaction of intense electromagnetic waves with plasma and the heating of dense plasma by intense radiation, in particular its heating in tokamaks using electron cyclotron resonance. He was the first to study electromagnetic shock waves, theoretically (with G. I. Freidman) and experimentally (with I. G. Kataev), as well as some self-oscillating wave systems.