CONTROL AND EFFECT OF LONG-PULSE DISCHARGE IN ATF

A 4667-second long discharge has been obtained in the ATF torsatron. T he total amount of the energy input was 330MJ. The set-up procedures, the control of plasma parameters, and the effect on the wall condition ing for the long pulse discharge are reported in this paper. Fast dens ity feedback control is not useful for a long-pulse operation; control of the neutral pressure on a slower time scale is necessary. Long-pul se discharges are quite effective for wall conditioning. Valuable expe riences have been accumulated in the future experiments planned for LH D.