Influence of sawtooth oscillations on fast ions in a stellarator

Abstract

Sawtooth oscillations in tokamaks frequently lead to the redistribution of energetic ions, mainly on passing orbits, causing their expulsion from the core. This paper discusses the first measurements of the interaction of fast ions and sawteeth in the Large Helical Device. The crashes were caused by the plasma current induced by Electron Cyclotron Current Drive and Neutral Beam Current Drive. Despite these crashes, there was no detectable redistribution effect on fast ions in either the core or at the edge of the plasma.