Measurements of Tritium Recycling and Isotope Exchange in TFTR
Authors: C H Skinner, J Kamperschroer, D Mueller
Tritium Balmer-alpha (Ta) emission, along with Ha and Da, is observed in the current D-T experimental campaign in TFTR. The data are a measure of the fueling of the plasma by tritium accumulated in the TFTR limiter and the spectral profile maps neutral hydrogenic velocities. Ta is relatively slow to appear in tritium neutral beam heated discharges, (Ta /(Ha+Da+Ta) = 11% after 8 tritium-only neutral beam discharges). In contrast, the Ta fraction in a sequence of six discharges fueled with tritium puffs, increased to 44%. Larger transient increases (up to 75% Ta) were observed during subsequent tritium gas puffs. Analysis of the Doppler broadened spectral profiles revealed overall agreement with the dissociation, charge exchange, sputtering and reflection velocities predicted by the neutral Monte-Carlo code DEGAS with some deficiency in the treatment of dissociation products in the 10-100 eV range.