Large potential change induced by pellet injection in JIPP T-IIU tokamak plasmas

摘要

A large, rapid change in the local plasma potential is found to be induced by off-axis hydrogen ice pellet injection into a tokamak plasma. The polarity of the change during the ablation is reversed when the pellet is injected into the upper and lower halves of the poloidal plasma cross-section. This change can be interpreted as being due to the Del B drift of particles in the high density plasmas of the pellet cloud, before the increase of the plasma density due to the ablation becomes uniform on the magnetic surface.