Recent progress in the increase in power and frequency of microwave sources has been caused by the development a new branch of physics which can be called high-frequency relativistic electronics. Microwave tubes based on relativistic electronics are called gyrodevices.

A gyrotron microwave oscillator developed by the Japan Atomic Energy Research Institute is used in this study. Frequency and output power is 170GHz and 1MW, respectively. Its pulse duration is up to 10sec. This microwave sources have been developed for International Thermonuclear Experimental Reactor (ITER).