MODIFICATION OF TOKAMAK EDGE TURBULENCE USING FEEDBACK

Using active feedback, the turbulent fluctuation levels have been redu ced by as much as a factor of 2 in the edge of the Texas Experimental Tokamak (TEXT) [K. W. Gentle, Nucl. Fusion Technol. 1, 479 (1981)]. A probe system was used to drive a suppressor wave in the TEXT limiter s hadow. A decrease in the local turbulence-induced particle flux has be en seen, but a global change in the particle transport at the present time has not been observed. By changing the phase shift and gain of th e feedback network, the amplitude of the turbulence was increased by a factor of 10.