Design of collection optics and port-plug for Thomson scattering system in JT-60SA

Tojo, Hiroshi; Hatae, Takaki; Sakuma, Takeshi; Hamano, Takashi; Shinohara, Koji; Itami, Kiyoshi; Aida, Yoshiaki*; Suito, Satoshi*; Fujie, Daijiro*

Conceptual designs of the collection optics for JT-60SA Thomson scattering have been done. Adapting four glass materials of the lenses used for the collection optics enables to correct the chromatic aberrations with good resolution ( 1 mm). The whole radial profile can be measured using three designed collection optics in Port-P1, P2 and P5. The collection optics will be installed in port-plugs accessing from the cryostat to vacuum vessel. In a disruption with a decrease of the plasma current by a time scale of 5 MA/8 ms, the eddy current (0.1 MA/m) is strongly generated in the area of 500 mm from the edge of the port-plug with the thickness of 30 mm. Even if the thickness is reduced to 20 mm decreasing the current in the area, the maximum principal stress is still under the limit value for the design.