Observations of plasma rotation in the high beta Tokamak Torus II

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Abstract
Toroidal and poloidal plasma rotation are measured in a high beta Tokamak device by studying the Doppler shift of the 4686 AA He II line. The toroidal flow motion is in the same direction as the plasma current at an average velocity of 1.6*106 cm s-1, a small fraction of the ion thermal speed. The poloidal flow follows the ion diamagnetic direction, also at an average speed of 1.6*106 cm-1. In view of certain ordering parameters, the toroidal flow is compared with the predictions of neoclassical transport theory in the collisional regime. For the poloidal motion, however, it is likely that an (Er*B)/B2 drift in a positive radial electric field, approaching a stable ambipolar state (Stringer, 1970) is responsible. Mechanisms for the time evolution of the rotation are also examined. The radial electric field responsible for the (Er*B)/B2 drift is determined from the theory using the measured poloidal velocity.