GLOBAL PARTICLE RECYCLING WITH OHMIC AND NEUTRAL BEAM HEATING IN TFTR

High I//p, high n//e TFTR discharges exhibit a strong density increase throughout most of the period of 0. 5 s neutral beam pulses. This increase is consistent with beam fueling. On the other hand, low I//p, low n//e discharges show n//e saturation shortly after the beam turn-on. The latter phenomenon has been observed in smaller devices operated at lower I//p ('density-clamping'). The H// alpha emission near the limiter shows a strong density and plasma current scaling left bracket (n OVER BAR //e/I//p)**3 right bracket but shows little change with beam power toroidal field, and plasma species, or with a change in wall condition (with and without Cr gettering and ZrAI gettering.