Progress on electron cyclotron heating antenna design for JT-60SA

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

Capabilities of the transmission power of 0.8 MW and pulse duration of 100 s, and two dimensional beam steering both in poloidal and toroidal directions are required for electron cyclotron (EC) heating antenna in JT-60SA. An antenna based on a linear-motion concept has been designed. Recently, rf profiles for various poloidal/toroidal beam angles were measured using mock-up mirrors and a low power millimeter wave source. It was confirmed that the beam direction and profile of the antenna were agree with the numerical design. Moreover, some candidates of the support structure of the steering shaft were considered and one of them, which used a small sliding bearing, was tested by a mock-up. In this test, smooth movement in vacuum condition was confirmed. An extention of the operation regime of the system by means of dual frequency EC waves has been studied. Results of evaluation of the antenna steering range for this purpose is also presented.