NOBLE-GAS PUMPING BY THE TFTR GRAPHITE LIMITER

[摘要] The TFTR limiter is graphite. It is possible to decrease the amount of D trapped in the limiter by making plasma discharges with gas injected only as a prefill. When the limiter is deuterium depleted well enough by this technique for supershots (with R(D) approximately 0.5-0.6) it pumps noble gases. The effective confinement time tau(p)* ranges from less-than-or-equal-to 1 s for He down to 0.08 s for Kr. These noble gases escape from the limiter slowly after the run. The partial pressures of Ar and Ne decay with time constants of several hours, and the data for Ar show evidence of two trapping sites.

[发布日期] 1992-12-01