Analytical and numerical studies of ion mobility near the tokamak plasma edge

摘要

The effects of radial electric field on charged particle motion and transport in a toroidal magnetic system have been studied both analytically and numerically. We examine the effects of radial electric field on particle orbits, allowing for the relatively large and strongly sheared field observed in some experiments. We find that ion radial mobility due to the combined effects of radial electric field and charge exchange collisions can dramatically affect the ion transport and orbit loss near the tokamak edge. These properties may help us understand the formation of transport barrier near the H mode plasma edge and explain the asymmetry between bias voltage and confinement in biased-electrode-induced H mode.