Development of high power 170 GHz gyrotron for ITER

The development of a 170 GHz gyrotron is underway for the ITER application. Up to now, experimental results of 0.5 MW/100 sec, 0.9 MW/9.2 sec were demonstrated. For a stable 1 MW/CW operation, the gyrotron and test facility are under modification: an efficiency improvement of built-in mode converter, beam current control with a pre-programmed control of a cathode heater power, and voltage between an anode and a cathode for constant output power. These contributes to the further stable 1 MW power output in long pulse operation.