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 ³He minority ion species in a ⁴He majority plasma in the Princeton Large Torus. The energetic ³He 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 ³He⁺⁺ + ⁴He⁰ → ³He⁰ + ⁴He⁺⁺ demonstrated in these measurements may be useful as part of an alpha particle diagnostic in a fusion reactor experiment.