The effects of ICRF heating on plasma edge conditions in PLT

Abstract

The interaction of ICRF heating with the plasma edge in Princeton large torus (PLT) is reviewed and possible mechanisms responsible for the observations are discussed. Ion and neutral sputtering are found to be the most significant producers of impurities, which are observed to increase in moderate amounts during ICRF heating. Collisional edge heating by the rf is evaluated as a possible explanation of measured electron density increases and particle fluxes. Antenna conditioning is also discussed, relating to the processing necessary to achieve the highest power handling capability per antenna in PLT.