Relativistic microwave electronics

High-power electronics based on the use of relativistic-electron beams started to be actively developed in the early 1970s, after high-current accelerators of charged particles had been created in Russia and abroad. The first generator of the coherent electromagnetic radiation, which was excited by the high-current electron accelerator, the relativistic backward-wave oscillator (BWO), was created upon an initiative of A. V. Gaponov-Grekhov and M. S. Rabinovich in a joint experiment of the Radiophysics Research Institute and Lebedev Physical Institute of the Academy of Sciences (N. F. Kovalev, M. D. Raizer, M. I. Petelin, A. V. Smorgonskiy, and L. E. Tsopp). In terms of the pulse power, this generator exceeded all earlier microwave sources by several orders of magnitude.

Later, the IAP team proposed and realized experimentally (in many cases, jointly with other Russian and foreign laboratories) relativistic modifications of other well-known weakly relativistic electron microwave generators and amplifiers based on all known mechanisms of stimulated emission of particles, specifically, traveling-wave tubes, orotrons, magnetrons, gyrotrons, etc. (М. I. Petelin, N. F. Kovalev, V. L. Bratman, N. S. Ginzburg, E. B. Abubakirov, G. G. Denisov). Fundamentally new variants of free-electron masers have also been created, specifically, the cyclotron-autoresonance maser (CARM) and the ubitron with distributed feedback and high Doppler conversion of the radiation frequency.

Currently, the following research fields of relativistic microwave electronics are developed at IAP:

  • increase in the average radiation power;
  • development of gyrotrons and gyroklystrons operated at high-order volume modes;
  • study of free-electron masers (FEMs) with one-dimensional and two-dimensional distributed feedback;
  • creation of generators of subnanosecond microwave pulses, which are based on the effect of superradiation of extended electron bunches;
  • realization of multi-gigawatt peak power sources based on the combination of relativistic generators and pulse compressors.