FORMATION OF OSCILLATING PERPENDICULAR ELECTRIC-FIELD BY AC LIMITER BIASING ON HYBTOK-II TOKAMAK

It will be necessary to establish the divertor that will withstand the spatially peaked thermal loads for future long pulse or steady state fusion reactors. In this research, formation of the oscillating electric field perpendicular to the magnetic field in a tokamak scrape-off layer and its application to the broadening of the divertor heat load are discussed. An AC biasing voltage between 5 to 100 kHz is applied to poloidal limiters and time responses of the plasma potential and electric field in the edge region is studied. The oscillating electric field both in the radial and poloidal directions is excited by AC limiter biasing and significant penetration of the electric field into a core region was observed. The radial excursion of the charged particle due to the oscillating E(p) X B-l drift in the radial direction is estimated to be as large as the SOL width.