Behavior of Hydrogen Fueled by Pellet Injection in the GAMMA 10 Tandem Mirror

Abstract

In the GAMMA 10 tandem mirror, the pellet injection system is installed near the mid-plane of the central cell to improve plasma parameters and to study the pellet-plasma interactions in an open system. In recent experiments, hydrogen pellets are injected with ECRH at the plug/barrier and central cells. Consequently, increases in electron densities and H_α line emission with three peaks are observed. The radial profiles of H_α line emission at the peak time have a peak in the peripheral region of the injection side. These results show that the pellet cracks into three small pieces somewhere of the injection path. In this discharge, the pellet of the third peak penetrates deeper than the pellet of first peak, although the third pellet smaller than the first pellet. This phenomenon is occurred by the decrease of the ion temperature caused by the first and second pellet.