Achievement of 1.5 MW, 1 s oscillation by the JT-60U gyrotron

Kobayashi, Takayuki; Moriyama, Shinichi; Seki, Masami; Sawahata, Masayuki; Terakado, Masayuki; Fujii, Tsuneyuki

Gyrotrons are used for electron cyclotron heating (ECH) / current drive (ECCD) as high power millimeter wave sources in high performance plasma experiments. Pulse length from 0.1 to several seconds with high power is required in present tokamak experiments, such as JT-60U. However, 0.1 s oscillation had only been achieved in the power level of 1.5 MW. In JAEA, high power and long pulse oscillation experiments by using the latest JT-60U gyrotron have been tried to achieve power level of 1.5 MW and pulse length over 1 s. As a result, 1.5 MW/1 s oscillation has been successfully achieved by the fine optimization of operation parameters. In this paper, the first results of the oscillation experiment of 1.5 MW for 1 s and future plans of gyrotron improvements are described.