INVESTIGATION OF RECYCLING IN THE GAMMA-10 TANDEM MIRROR

This paper describes the detailed behavior of particle recycling on the stainless-steel wall of the GAMMA 10 tandem mirror device. A comparison is made with a model calculation. The ion temperature dependence of the recycling coefficients has been deduced from experimental data in a wall conditioning period. It was found that the recycling coefficient increased with the ion temperature and that the recycling due to particles desorbed from the wall prevailed over that due to wall-reflection. A simple recycling model including both atomic and molecular processes was applied for the ICRF-heated plasma. The result of the model calculation is consistent with the above ion-temperature dependence. The DEGAS neutral transport code has been applied to the GAMMA 10 configuration and the results of the DEGAS code show a good agreement with results obtained from H(alpha)-emission, which predicted a significant influence due to neutral molecules near the plasma boundary.