AbstractA motional Stark effect polarimeter with five viewing points has been installed to obtain current profiles in the JT-60U tokamak. Offset angles caused by Faraday rotation were calibrated by rapidly moving a plasma, keeping the q profile unchanged. Polarized background light was observed and its effect was corrected by detecting the light which had a wavelength close to that of the beam emission. Current profiles in a current rampdown discharge were measured, and the q value at the inversion radius of the sawtooth oscillation agreed with the theoretical value (unity) within 10%.
モーション・スターク効果偏光計を5視点で設置し、JT-60Uトカマクにおける電流分布を取得した。ファラデー回転によるオフセット角は、q分布を一定に保ったままプラズマを高速移動させることで較正した。偏光した背景光の影響を観測し、ビーム発光と近い波長の光を検出することで補正した。電流ランプダウン放電における電流分布を測定し、鋸歯状振動の反転半径におけるq値は理論値（1）と10%以内で一致した。