Pumping effect on the divertor plasma and detachment in the JT-60U W-shaped divertor

Effects of the divertor pumping on the SOL plasma flow and neutral recycling were investigated under high density and detached divertor conditions, using reciprocating Mach probes at the outer midplane and just below the divertor x-point. For the divertor pumping from inner and outer sides of the private dome (both-sides pumping), plasma flow in the outer divertor was increased compared to that for the inner-side pumping case (i.e., closing the outer pumping slot) when the plasma detachment appeared on the divertor target. Partially detached plasma was maintained at the inner and outer divertor without causing x-point MARFE, and in-out symmetrical profiles of D-alpha brightness and ion flux were observed. (C) 2001 Elsevier Science B.V. All rights reserved.