Large Orbit Gyrotron as High-Power Far-Infrared Radiation Source

Summary form only given. A large orbit gyrotron (LOG) has been developed for generation of high-power far-infrared radiation. It uses pulsed relativistic electron beam with maximum electron energy of 400 kV. The studies were carried out through both experimental and simulation approaches. The objective is to demonstrate high-power radiation in terahertz range. The experiments were carried out using repetitive pulsed power generator "ETIGO-IV". Relativistic electron beam is accelerated and injected into the interaction cavity where pulsed magnetic field of 10 T is applied. The electron-beam current and the electron momentum pitch-factor were optimized by adjusting the CW magnetic field which is applied in the opposite direction to the pulsed field. The electromagnetic radiation from LOG was extracted along a cylindrical waveguide and radiated into the air through a quartz window. Diagnostics were carried out for radiation power and frequency. Numerical simulations were carried out by using three- dimensional particle-in-cell simulation code "\´MAGIC". The simulation model covers both the electron-beam diode and the interaction cavity. For electron acceleration and propagation, particle behavior is analyzed in both real and phase spaces. For the resonant cavity, the studies have concentrated on mode control and conversion efficiency. The simulation results have been used to optimize the diode geometry and the cavity dimensions.