Improving the efficiency of submillimeter gyrotrons by using various electrodynamic systems

At present, interest to submillimeter devices, has been strengthened since this frequency range is attractive for numerous applications, which include plasma diagnostics, electron-spin resonance spectroscopy, enhancement of NMR sensitivity using dynamic nuclear polarization, standoff detection and imaging of explosives and weapons, new medical technology, atmospheric monitoring, chemical technologies, production of high-purity materials, deep space and specialized satellite communication etc. One of these devices is a gyrotron. The main problems of gyrotron optimization and development are mode competition between operating and parasitic modes and wideband frequency tuning. In this paper, some types of electrodynamic systems for creating submillimeter gyrotrons are investigated. For gyrotrons with the two-mirror cavity the possibility of wideband frequency tuning (50%), with and maintaining high efficiency (about 1%) is shown. Also the 2 THz gyrotron based on the using couple cavity was presented. Optimization of the cavity and the problem of mode selection were investigated and its efficiency were estimated.