ELECTRON-TEMPERATURE MEASUREMENT USING THE LINE-INTENSITY RATIO ON THE CTCC SPHEROMAK

Line-intensity ratio measurements of the electron temperature have bee n successfully made on the CTCC-II spheromak. The electron temperature s obtained in the core plasma are 20-80 eV, which are consistent with the values obtained by Thomson scattering. This measurement has the ad vantage of giving the time evolution of the electron temperature withi n a single plasma discharge. In the CTCC spheromak, intermittent insta bility (stepwise instability) and its relaxation are frequently observ ed. During the stepwise instability and its relaxation cycles, increas e and decrease in the temperature are observed in the current-profile- peaking phase and the nonlinear saturation phase of the n = 2 mode. It is demonstrated that the temperature profile in the peripheral plasma can be controlled by an additional magnetic field (choking field), wh ich can reduce the error field in the entrance hole of the flux conser ver.