Progress Of High Power Gyrotron Development In Jaea

Recent progress on a high power 170 GHz gyrotron development in JAEA is presented. After the demonstration of ITER basic performance, the gyrotron has been operated for 3 years, and recorded similar to 200 GJ of total output energy. As a next activity, a study of a CW-power modulation of the gyrotron for NTM (Neo classical Tearing Mode) stabilization has started. Up to now, power modulation of 5 kHz for short pulse, and 0.31cHz for 5 min were demonstrated at similar to 0.8 MW. The efficiency of 50 % was kept at each pulse. On the other hand, a gyrotron capable to operate at two frequencies has been designed and fabricated. A first oscillation of 1 MW at dual frequencies of 170 GHz and 137 GHz was demonstrated.