Development and experimental investigations of high power THz gyrotrons

Terahertz waves are promising for diagnosis and spectroscopy of various media, including the development of high resolution electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopy. Powerful terahertz radiation can be used to create dense plasma and control its parameters (controlled thermonuclear fusion, “point” plasma X-ray sources, remote detection of ionizing radiation). In the pioneering IAP RAS works in 1970-1980´s was shown the principle possibility of a high-power CW and pulsed gyrotrons operation at frequencies from 0.33 to 0.65 THz. In recent years a number of new results at the development of THz band gyrotrons has been obtained at IAP (see, for detail, review [1-4]). This report will focused at two of them - the penetration of gyrotrons in the frequency range above 1 THz and generation of hundreds kW power at THz band. The experiments based on the original pulsed solenoid with a magnetic field up to 50 T yielded generation on the main cyclotron resonance with 5-0.5 kW power in single pulse duration of 50 microseconds at record frequencies 1-1.3 THz [5,6] and with pulsed power up to 200 kW at 0.7 THz band [7].