(FT/P2-26) Long Pulse/High Power ECRF System Development in JT-60U

S.M. Moriyama1), T. Kobayashi1), A. Isayama1), M. Terakado1), M. Sawahata1), S. Suzuki1), K. Yokokura1), M. Shimono1), K. Hasegawa1), S. Hiranai1), K. Igarashi1), F. Sato1), T. Suzuki1), K. Wada1), S. Shinozaki1), M. Seki1), A. Kasugai1), K. Takahashi1), K. Kajiwara1), K. Sakamoto1), T. Fujii1)
 
1) Japan Atomic Energy Agency, Naka, Ibaraki, Japan

Abstract.  In the recent gyrotron development in JT-60U ECRF system, 1.5 MW for 1 s of the world highest power oscillation (> 0.1 sec) has been achieved at 110 GHz. In addition to the carefully designed cavity and collector in view of thermal stress, an RF shield for the adjustment bellow, and a low-loss DC break enabled this achievement. Moreover as a development step to realize a reliable ECRF system in future fusion experiments, long pulse demonstration of 0.4 MW, 30 s injection to the plasma has been achieved. It has been confirmed that the temperature of cooled components are saturated and no evidence of damage were found in the waveguides and antenna without forced cooling. As a forced cooling antenna for longer pulse in future, an innovative antenna having relatively wide range of beam steering capability with linearly-moving-mirror concept has been designed. Beam profile and mechanical strength analysis shows the feasibility of the antenna.

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