Suppression of Metallic Impurities by Electron Injection in a Tokamak

Abstract

We found that the sheath potential plays a dominant role in the plasma-wall interaction in the Macrotor tokamak. An increase in the sheath potential, produced by removing electrons from the plasma, results in the enhancement of the metal influx. When the sheath potential is reduced by electron injection, the metal influx is suppressed. This mechanism may be used as a tool in controlling metallic impurities in tokamaks.