Theoretical and experimental investigations of submillimeter CW gyrotrons

This paper presents an overview of research activity for development of relatively low-power (10100 W) submillimeter CW gyrotrons at the IAP RAS. Those investigations were started in the 1970-80s and several tubes with unique parameters have been developed. This time at the IAP RAS were obtained recordbreaking results of power and frequency of radiation (1.5 kW for 0.3 THz CW gyrotron at the second harmonic of gyrofrequency). During the end of the 20-th century main efforts were concentrated on development of megawatt power level gyrotrons for nuclear fusion experiments and submillimeter wave activity was rather slackened. 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.