Sensitivity study of the ITER poloidal polarimeter

Yamaguchi, Taiki; Kawano, Yasunori; Kusama, Yoshinori

The poloidal polarimeter will be installed in the International Thermonuclear Experimental Reactor (ITER) to measure the profile of the toroidal current (safety factor) in the plasma core region. For the optimization of the viewing chord arrangement of the ITER poloidal polarimeter, we studied the sensitivity of the viewing chord arrangement on the current profile. We proposed the new method for the sensitivity study, in which the Faraday rotation angle due to the toroidal current only is used as the sensitive index. As the result, we could find the viewing chords which are sensitive to the central current density, the finite beta effect and the ratio of the central current density and the maximum current density in case of the hollow current profile. Next, we proposed the viewing chord arrangements which are sensitive to the current profiles of ITER operation scenarios.