FEEDBACK-CONTROL AND STABILIZATION EXPERIMENTS ON THE TEXAS EXPERIMENTAL TOKAMAK (TEXT)

Plasma edge feedback experiments on the Texas Experimental Tokamak (TE XT) have been successful in controlling the edge plasma potential fluc tuation level. The feedback wave-launcher is driven by the local edge potential fluctuations. The edge potential fluctuations are modified i n a broad frequency band. Moreover, the potential fluctuations can be reduced (less than or equal to 100 kHz) without enhancing other modes, or excited (10 to 12 KHz), depending on the phase difference between the driver and the launcher signal, and gain of the system. This turbu lence modification is achieved not only locally but also halfway aroun d the torus and has about 2 cm of poloidal extent. The local plasma pa rameters at the edge and the estimated fluctuation-induced radial part icle flux are somewhat affected by the edge feedback.