Session RP1 - Poster Session VIII.
POSTER session, Thursday afternoon, October 30
Fran Hill Southeast Exhibit Hall, ACC
The deuterium and helium dynamics in the plasma and subdivertor regions of JET are compared during a sequence of similar ohmic and NBI pulses where 100% He gas is injected into the JET vacuum vessel, whose graphite walls were previously saturated with deuterium. After the first six He fueled change-over discharges, only He plasma operation was performed. The He concentration is measured in the sub-divertor with a species selective Penning gauge. Comparison of the time dependence of the divertor concentrations with those at the edge and strike point shows significant differences during the first six discharges. Data has been obtained for both the normal and reversed toroidal magnetic field direction. These differences along with a global He particle balance is used to assess the status of the wall saturation over the initial 6 - 7 He change-over discharges.