Abstract-Theoretical and Experimental Investigations of Terahertz-Range Gyrotrons with Frequency and Spectrum Control

G. G. Denisov, M. Y. Glyavin, A. E. Fedotov,  I. V. Zotova

https://link.springer.com/article/10.1007/s10762-020-00672-8

We present the results of recent IAP RAS investigations, which were aimed at controlling the radiation frequency and spectrum of THz-range medium-power gyrotrons. Problems of extending the smooth frequency tuning band and providing high-frequency stability in CW regimes are discussed. The development of gyrotrons with stated parameters are of interest for many modern applications, including DNP/NMR and RAD spectroscopy, direct measurements of positronium hyperfine structure, and diagnostic of various media.

Abstract-Terahertz-Range High-Order Cyclotron Harmonic Planar Gyrotrons with Transverse Energy Extraction

I. V. Zotova, N. S. Ginzburg, A. M. Malkin, V. Yu ZaslavskyI. V. Zheleznov, A. S. Sergeev, M. Yu Glyavin, S. Mitsudo, Y. Tatemasu, T. Idehara

https://link.springer.com/article/10.1007%2Fs10762-019-00661-6

We develop a multi-mode time-domain model for theoretical description of mode competition in a planar gyrotron with sheet beam of rotating electrons and transverse energy extraction. Within the frame of this model, we demonstrate an improvement of mode selectivity and power increasing in the case of excitation of high-order cyclotron harmonics in terahertz-range planar gyrotrons. The obtained results are confirmed based on direct 3D PIC (particle-in-cell) simulations.

Abstract-Energy Spectra of Electron Beams and the Possibility of Double-Stage Energy Recuperation in a Double-Beam Terahertz Gyrotron

M. Yu. Glyavin, V. Yu. Zaslavsky, I. V. Zotova, V. N. Manuilov, A. P. Fokin,

https://link.springer.com/article/10.1007/s11141-019-09981-y

We study theoretically the possibilities of double-stage energy recuperation in a double-beam terahertz gyrotron. Numerical modeling, which was performed for a gyrotron producing radiation with a frequency of 0.78 THz and operating at the second cyclotron-frequency harmonic at the TE8.5 mode, demonstrates the possibility of spatial and energy separation of electron beams. This makes it possible to implement a double-stage recuperation scheme. The found energy spectra of electrons suggest an increase in the gyrotron efficiency by 3.5–4 times.

Abstract-Generation of subterahertz-superradiance pulses based on excitation of a surface wave by relativistic electron bunches moving in oversized corrugated waveguides

N. S. Ginzburg, A. M. Malkin, A. S. Sergeev, I. V. Zheleznov, I. V. Zotova, V. Yu. Zaslavsky, G. Sh. Boltachev, K. A. Sharypov, S. A. Shunailov, M. R. Ul’masculov, and M. I. Yalandin

https://journals.aps.org/prl/accepted/5d073Y8eG861f051b61816e2430e18bd13acaaafd

The first experiments on observation of short pulsed superradiant (SR) emission with excitation of a surface wave by a relativistic electron bunch moving in oversized corrugated waveguide were performed. Sub-terahertz SR pulses with the central frequency of 0.14 THz, ultrashort duration of 150 ps and an extremely high peak power of 50-70 MW were generated. The experiments were based on a theoretical consideration including the quasi-optical approach and direct particle-in-cell simulations.

Abstract-3D quasioptical theory of terahertz superradiance of an extended electron bunch moving over a corrugated surface

http://prl.aps.org/accepted/8b07fYcaNd414e30a8d77a25ef1688040713983d1
N. S. Ginzburg, A. M. Malkin, A. S. Sergeev, I. V. Zotova, V. Yu. Zaslavsky, and I. V. Zheleznov

We consider the superradiance of an extended relativistic electron bunch moving over a periodically corrugated surface for the generation of multi-megawatt terahertz pulses. To study the above process we have developed a three-dimensional, self-consistent, quasi-optical theory of Cherenkov stimulated emission which includes a description of the formation of an evanescent wave over a corrugated surface and its excitation by RF current induced in the electron bunch.