Active density control with ergodic divertor and pump limiters on Tore Supra

Abstract

Active plasma density control with the ergodized boundary layer has been achieved in Tore Supra with the plasma leaning on the ergodic divertor and on the vertical pump limiters. Ohmic experiments are reported which show that active pumping yields a satisfactory exhaust capability. It is also shown that the wall particle content is partially depleted by the active pumping and that no modification of the radiated power fraction is recorded with active pumping. Plasma density control can be achieved with 70% of radiated power in steady state with intrinsic impurities, but when the radiated power reaches 100%, the plasma density cannot be actively controlled.