Optical design of EC launcher in JT-60SA

Kobayashi, Takayuki; Isayama, Akihiko; Hiranai, Shinichi; Sawahata, Masayuki; Terakado, Masayuki; Wada, Kenji; Sato, Yoshikatsu; Hinata, Jun; Yokokura, Kenji; Hoshino, Katsumichi; Takahashi, Koji; Kajiwara, Ken; Oda, Yasuhisa; Ikeda, Ryosuke; Moriyama, Shinichi; Sakamoto, Keishi

An original design of the toroidal injection angle range of electron cyclotron waves in JT-60SA was -15 degree to +15 degree for effective use of 110 GHz wave. However, the modification of the toroidal angle range has been discussed since the frequency of 138 GHz is considered to be a second frequency by the use of a dual frequency gyrotron. We report newly calculated available steering range of the launcher on both poloidal and toroidal angles with and without tilting angle of the second mirror, which is considered to obtain large toroidal injection angle. Moreover calculated beam divergences for various curvature radiuses of the first and second mirrors are shown. The decision of the target injection angle range for JT-60SA initial plasma will be made by the JT-60SA physics team by taking into account the above calculation results.