EXPERIMENTAL-OBSERVATIONS OF THE DYNAMICS OF PELLET ABLATION ON THE TEXAS EXPERIMENTAL TOKAMAK (TEXT)

The toroidally aligned filaments which are commonly observed to be formed by the ablation of a hydrogen fuelling pellet have been studied in TEXT. The ablatant forms the first distinguishable filament near a critical radius, which appears to be that of the q=2 surface. The positions of the other filaments can be predicted from the ballistic motion of the pellet and a simple time dependent model for pellet ablation. These experimental results indicate that a time dependent model may be required as a refinement of present ablation models. © 1990 IOP Publishing Ltd.