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-Excitation of Hybrid Space-Surface Waves in Clinotrons with Non-uniform Grating

E. M. Khutoryan, Yu. S. Kovshov, A. S. Likhachev, S. S. Ponomarenko, S. A. Kishko, K. A. Lukin, V. V. Zavertanniy, T. V. Kudinova, S. A. Vlasenko, A. N. Kuleshov, T. Idehara,

https://link.springer.com/article/10.1007/s10762-017-0453-3

Excitation of surface (slow), space (fast), and hybrid surface-space waves in BWO-clinotron with periodically non-uniform grating has been studied both theoretically and experimentally. It is shown that an interaction of electron beam with hybrid surface-space wave may be more effective than with surface wave because of higher Q-factor, and than with space wave because of higher impedance. The experimental test results of both 100-GHz CW clinotron with non-uniform three-stage grating and of 130-GHz CW clinotron with four-stage grating showed the excitation of radiation with output power more than 1 W and some specific features of electronic frequency tuning.

Abstract-Simultaneous Stabilization of Gyrotron Frequency and Power by PID Double Feedback Control on the Acceleration and Anode Voltages

https://link.springer.com/article/10.1007/s10762-017-0374-1

• • 
    
• E. M. KhutoryanEmail author
• T. Idehara
• A. N. Kuleshov
• Y. Tatematsu
• Y. Yamaguchi
• Y. Matsuki
• T. Fujiwara
• In this paper, we present the results of simultaneous stabilization of both the frequency and the output power by a double PID feedback control on the acceleration and anode voltages in the 460-GHz gyrotron FU CW GVI, also known as “Gyrotron FU CW GO-1” (according to the nomenclature adopted at Osaka University). The approach used in the experiments is based on the modulation of the cyclotron frequency and the pitch factor (velocity ratio) of the electron beam by varying the acceleration and the anode voltages, respectively. In a long-term experiment, the frequency and power stabilities were made to be better than ±10−6 and ±1%, respectively.

Development and Applications of High—Frequency Gyrotrons in FIR FU Covering the sub-THz to THz Range

My Note: This interesting piece is taken from Doc Maly's blog "The DNP-NMR Blog"
http://blog.bridge12.com/

Idehara, T. and S. Sabchevski, Development and Applications of High—Frequency Gyrotrons in FIR FU Covering the sub-THz to THz Range. J. Infrared Millim. Te., 2012. 33(7): p. 667-694.

http://dx.doi.org/10.1007/s10762-011-9862-x

Powerful sources of coherent radiation in the sub-terahertz and in the terahertz frequency range of the electromagnetic spectrum are necessary for a great and continuously expanding number of applications in the physical research and in various advanced technological processes as well as in radars, communication systems, for remote sensing and inspection etc .. In recent years, a spectacular progress in the development of various gyro-devices and in particular of the powerful high frequency (sub-terahertz and terahertz) gyrotron oscillators has demonstrated a remarkable potential for bridging the so-called terahertz power gap and stimulated many novel and prospective applications. In this review paper we outline two series of such devices, namely the Gyrotron FU Series which includes pulsed gyrotrons and Gyrotron FU CW Series which consist of tubes operated in a CW (continuous wave) or long pulse mode, both developed at the FIR FU Center. We present the most remarkable achievements of these devices and illustrate their applications by some characteristic examples. An outlook for the further extension of the Gyrotron FU CW Series is also provided.