Plasma and Fusion Research

Volume 15, 1402051 (2020)

Regular Articles

Divertor Detachment with Multi-Species Impurity Seeding in LHD
Kiyofumi MUKAI1,2), Suguru MASUZAKI1), Yuki HAYASHI1), Tetsutaro OISHI1,2), Chihiro SUZUKI1), Masahiro KOBAYASHI1,2), Hirohiko TANAKA3), Byron J. PETERSON1,2) and the LHD Experiment Group1)
1)
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
2)
The Graduate University for Advanced Studies, SOKENDAI, Toki 509-5292, Japan
3)
Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
(Received 20 April 2020 / Accepted 2 June 2020 / Published 15 July 2020)

Abstract

Divertor detachment using higher-Z (Kr) and/or lower-Z (Ne) is investigated. Using Kr+Ne superimposed seeding, plasma radiation could be enhanced at the upstream region in the edge plasma with suppression of impurity accumulation toward the core plasma. Here, the pre-seeded Kr emission was drastically enhanced after the subsequent Ne seeding. Moreover, the detachment using Kr+Ne seeding could be stably sustained while the detachment using single species seeding is short-lived. Reduction of edge electron temperature due to Ne seeding can promote the Kr emission at the upstream region. It indicates the availability of multi-species impurity seeding with different cooling rate.

Keywords

divertor detachment, impurity seeding, stable sustainment, superimposed seeding, radiation profile

DOI: 10.1585/pfr.15.1402051

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