Plasma and Fusion Research

Volume 14, 2402109 (2019)

Regular Articles

Dynamic Response of Plasma Detachment Caused by Molecular Activated Recombination to Transient Particle Flux in GAMMA 10/PDX
Akihiro TERAKADO, Mizuki SAKAMOTO, Naomichi EZUMI, Kunpei NOJIRI, Tomohiro MIKAMI, Yosuke KINOSHITA, Satoshi TOGO, Takaaki IIJIMA and Yousuke NAKASHIMA
Plasma Research Center, University of Tsukuba, Tsukuba 305-8577, Japan
(Received 30 September 2018 / Accepted 9 December 2018 / Published 11 July 2019)

Abstract

The dynamic response to a particle flux in a divertor simulation plasma has been studied using electron cyclotron heating (ECH) in GAMMA 10/PDX. Hydrogen gas was supplied to the divertor simulation experimental module (D-module), and ECH was applied to the main plasma. The electron temperature (Te) decreased, and a rollover of electron density (ne) was observed upon an additional supply of hydrogen gas with and without ECH, which indicates that the plasma was detached. Moreover, the intensity of Hα (IHα) increased even though ne decreased with an increasing gas supply, indicating that the plasma detached due to molecular activated recombination (MAR). In the case of additional gas supply, ne increased, but Te was not affected by ECH. The ionization front moved to the upstream side, and the particle flux flowing into the D-module increased with ECH. The ratio of IHα to the intensity of Hβ (IHβ) near the corner of the V-shaped target increased with ECH, indicating that the MAR was enhanced near the corner. The intensity of the Fulcher-α Q1-branch increased near the corner of the V-shaped target with ECH, indicating that the density of hydrogen molecules was reduced by hydrogen recycling.

Keywords

GAMMA 10/PDX, divertor simulation experiment, plasma detachment, molecular activated recombination, dynamic response

DOI: 10.1585/pfr.14.2402109

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