Energetic Ion Measurements Using a Directional Probe

Abstract

A directional Langmuir probe (DLP) method has been applied to measurement of energetic particles (ions) in a magnetically confined plasma. Two experimental demonstrations were performed in the compact helical system (CHS). One was a neutral beam modulation experiment and the other was the measurement of energetic ion loss induced by MHD bursts. The results of the DLP were consistent with those of a neutral particle analyzer (NPA) and a lost ion probe (LIP). These experiments show that this method is applicable outside and also inside the last closed flux surface.