Recent Results of Experiments on Tandem Mirror Gamma 10

Potential confinement of an ICRF-heated high-ion temperature plasma in GAMMA 10 is experimentally studied. The potential confinement was shown from data of one-end plugging and both-end plugging. The waveform of end loss current and an analysis of end loss ion energies have also indicated potential formation and confinement. The central cell line density increases 50% by the potential confinement. Some radial losses were observed in the anchor and/or plug/barrier regions and a rate of the radial loss was measured by using the data from one-end plugging. Under an experimental condition, the radial loss rate was estimated to be about 3%. In order to reduce the radial loss, conducting plates were installed adjacent to the plasma in the anchor transition region. The density increase of 60 % was attained after installation of the conducting plates and a higher density increase can be expected in the near future. The density increase was 50% before installation of the conducting plates. Controllability and reproducibility of the potential confinement are also improved after installation of the conducting plates.