Plasma and Fusion Research

Volume 14, 2402032 (2019)

Regular Articles

Effect of the Potential of Confined Plasma on End-Loss Ion in GAMMA 10/PDX
Seowon JANG, Makoto ICHIMURA, Mafumi HIRATA, Ryuya IKEZOE1), Mizuki SAKAMOTO, Shuhei SUMIDA, Koki IZUMI, Atsuto TANAKA, Yushi KUBOTA, Ryo SEKINE, Hiroki KAYANO and Yousuke NAKASHIMA
Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
1)
Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
(Received 30 September 2018 / Accepted 7 January 2019 / Published 12 February 2019)

Abstract

In the GAMMA 10/PDX tandem mirror, studies on divertor physics have been performed in the west end region by utilizing end-loss plasmas flowing from the confinement region. Since the plasma density in the end region is quite low (∼ 1016 m−3), an increase of the end-loss ion flux is required. The increase of the end-loss ion flux has been obtained by increasing the density in the confinement region on previous experiments. When an additional ICRF heating using the antennas in the anchor cells has been performed, a significant increase of the ion flux has been observed with the increase of the potential in the central cell although the change of line densities in the confinement region is little. The effect of the potential on the ion flux has been examined on the GAMMA 10/PDX using about 10,000 discharges. The ion flux increases almost linearly with the potential and the density increase. By comparing with a simple calculation, the increase of the ion flux is explained by the expansion of loss cone boundary of ions and the decrease of the transport time of the end-loss ions from the confinement region to the end region.

Keywords

mirror confinement, end-loss ion, ion flux, potential, ICRF wave, GAMMA 10/PDX

DOI: 10.1585/pfr.14.2402032

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