Measurements of energetic helium-3 minority distributions during ion cyclotron radiofrequency heating in the princeton Large Torus

Ion cyclotron radiofrequency heating experiments were performed with a 3 He minority ion species in a 4 He majority plasma in the Princeton Large Torus. The energetic 3 He ion 'tail' was measured directly with a charge exchange neutral analyser for the first time. Comparisons with bounce averaged quasi-linear calculations suggest a modestly peaked radiofrequency power deposition profile. The double charge exchange process 3 He ++ + 4 He 0 → 3 He 0 + 4 He ++ demonstrated in these measurements may be useful as part of an alpha particle diagnostic in a fusion reactor experiment.