EFFECTS OF AN RF LIMITER ON TEXTORS EDGE PLASMAS

Studies directed towards the reduction of particle and heat fluxes to plasma facing components by the application of ponderomotive forces ge nerated by radio frequency (RF) are being conducted in TEXTOR. A modif ied poloidal limiter is used as an antenna with up to 3 kW of RF power ; the data obtained show that the plasma is repelled by the RF pondero motive potential. The density is reduced by a factor of 2-4 and the ra dial decay length is substantially altered. The density near the limit er decays exponentially with RF power. The electron temperature profil e changes, with the decay length becoming longer (almost flat) during the RF, The temperature in the scrape off layer (SOL) increases and it s increase is roughly proportional to the RF power until it saturates, suggesting that the heating efficiency drops with power, and that imp roved performance is to be expected at higher powers.