Progress in launcher developments for electron cyclotron heating and current drive in JT-60SA

Kobayashi, Takayuki; Moriyama, Shinichi; Isayama, Akihiko; Hiranai, Shinichi; Sawahata, Masayuki; Terakado, Masayuki; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; Sakamoto, Keishi

In JT-60SA, electron cyclotron heating and current drive (the maximum injection power of 7 MW with the longest pulse length of 100 s) is planned for various experimental objectives, such as electron heating, stabilization of instabilities and start-up assist. An two directional (toroidal and poloidal) beam steering capability is required for the launcher, which injects millimeter waves into plasmas. Moreover, active cooling of antenna mirrors is required for long pulse injection of 100 s. In order to satisfy the above requirements with high reliability, the launcher is being developed based on a linear-motion antenna concept. Recently, design of the steering mechanism using two bellows was improved to increase reliability. In the revised design, it is easy to replace one of the bellows, which is moved with large mechanical load. We also carried out an initial thermal analysis on the large curved mirror, and we obtained important knowledge on the making cooling channels in the mirror. In addition to the above results, we evaluated the transmission loss at the first mirror by including an higher order mode (LP11) of 10%. The estimated loss is smaller than 1% and acceptable.