Status of high power gyrotron development in JAEA

In JAEA, development of high power gyrotron is underway. One activity is a 1 MW/170 GHz gyrotron development for ITER application and another is a dual frequency (138GHz/110GHz) gyrotron for JT-60U. The advanced mode TE_31,11 was adopted for high power generation and multi-frequency operation. Up to now, 1.24 MW/2sec was obtained with DC input of 50 kV×55A, which is available by ITER power supply. In the multi-frequency operation, 1MW oscillation was obtained at three frequencies: 170 GHz, 137 GHz and 104 GHz. And, high efficiency long distance power transmission from the gyrotron window to the end of the 40 m transmission line were demonstrated: 91%, 89% and 84%, respectively. On the other hand, in the dual frequency gyrotron development, the power output of 1 MW/100 s, which is the target of the JT-60SA, were achieved for both frequencies (138 GHz/110 GHz).