Studies of boundary plasmas and fueling on the JFT-2M

Abstract In the JFT-2M tokamak, the effects of baffle plates on the divertor and the scrape-off-layer (SOL) plasma and the fueling by the compact toroid (CT) injection have been investigated, and following results were obtained. A transition-like phenomenon in the divertor plasma, which occurs at the average main plasma density of about 2–2.5 × 10 19 m −3 , was observed and coincides with the abrupt drop of the temperature on the divertor plate from 9 to 3 eV. The negative biasing of both inside and outside divertor plates showed a significant improvement of the buffled divertor function, which was only observed when the direction of the E  ×  B flow formed by the biasing in the SOL is from the inside to the outside. The particle fueling up to 3.4 × 10 18 was observed and increase of the W MHD and decrease of P RAD and V loop were observed in discharges with the CT injection in Ohmic heating (OH) plasmas.