Terahertz gyrotrons with quasi-regular cavities

Ivan V Osharin,Audrey V Savilov,Yury K Kalynov,Ilya V Bandurkin

doi:10.23919/ursigass.2017.8105117

Abstract

We describe two ways of the use in high-harmonic gyrotrons of quasi-regular cavities with short irregularities formed by the widening of cavity radius. The first one is a significant improvement of the selectivity of the second-harmonic gyrotrons due to the supression of parasitic near-cutoff fundamental-harmonic waves. The second approach is aimed to solve a typical problem of weakly-relativistic high-harmonics gyrotrons, namely, the use of long cavities ensuring extremely high diffraction Q-factors and a great share of Ohmic losses. We propose a quasi-regular cavity with periodic phase correctors, where a far-from-cutoff axial mode with a decreased diffraction Q-factor is excited in a gyrotron-like regime.

Highlights

We propose to modify the cavity of a 670 GHz gyrotron which presently operates in the Institute of applied physics (IAP) at the fundamental cyclotron resonance at the TE31,8 mode [3]
An analysis of the eigenmodes spectrum of this cavity shows that in the operating range of magnetic fields, the resonance is possible at the second cyclotron harmonic at the TE63,15 mode at 1.34 THz
In the traditional cylindrical system the starting current of this mode is slightly higher than the starting current of the lowfrequency modes TE30,8 and TE31,8 excited at the fundamental cyclotron resonance (Fig. 2)

Summary

Introduction

We propose to modify the cavity of a 670 GHz gyrotron which presently operates in the Institute of applied physics (IAP) at the fundamental cyclotron resonance at the TE31,8 mode [3]. An analysis of the eigenmodes spectrum of this cavity shows that in the operating range of magnetic fields, the resonance is possible at the second cyclotron harmonic at the TE63,15 mode at 1.34 THz. in the traditional cylindrical system the starting current of this mode is slightly higher than the starting current of the lowfrequency modes TE30,8 and TE31,8 excited at the fundamental cyclotron resonance (Fig. 2).

Results

Conclusion