Progress in development of JAEA gyrotron for ITER and high power experiments for multi-frequency oscillation

Ikeda, Ryosuke; Oda, Yasuhisa; Kobayashi, Takayuki; Terakado, Masayuki; Kajiwara, Ken; Takahashi, Koji; Moriyama, Shinichi; Sakamoto, Keishi

Electron cyclotron waves of 20 MW are injected to plasma by introducing 24 sets of 170 GHz gyrotron in ITER. JAEA procures 8 sets of gyrotron system. At present, we are developing TE31,11 mode gyrotron for ITER EC H & CD system. In 2 seconds operation, 1.24 MW / 45% and 1.13 MW / 49% were obtained. At the present moment, 0.6 MW / 1000 sec and 1.0 MW / 200 sec are achieved in steady-operation. Pulse lengths can be extended with continued aging. This TE31,11 mode gyrotron has also advantage for multi-frequency oscillation because radiation angle in the mode convertor is almost same for some TEm,n modes. By changing the magnetic field strength, frequencies such as 104 GHz (TE19,7), 137 GHz (TE25,9) and 203 GHz (TE37,13) are oscillated. The output power has achieved 1 MW for 104 GHz and 137 GHz in 2 seconds operation. Newly, 203 GHz oscillation was realized using a 8 T superconducting magnet and the output power of 0.85 MW was obtained in 1 ms short pulse operation.