Plasma and Fusion Research

Volume 9, 3402064 (2014)

Regular Articles

Measured and Modeled Radiation Profiles for LHD Plasma – A Comparison during Plasma Detachment

Shwetang N. PANDYA¹⁾, Byron J. PETERSON²⁾, Masahiro KOBAYASHI²⁾, Kiyofumi MUKAI²⁾, Ryuichi SANO¹⁾, Hirohiko TANAKA²⁾, Suguru MASUZAKI²⁾ and LHD Experiment Group

1): The Graduate University for Advance Studies, 322-6 Oroshi-cho, Toki 509-5292, Japan
2): National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan

(Received 26 November 2013 / Accepted 29 March 2014 / Published 10 June 2014)

Abstract

Detached (from the divertors) plasma regime is a very important operational phase for future fusion device operation and is sustained in the Large Helical Device (LHD) by applying an m/n = 1/1 resonant magnetic perturbation (RMP). The radiation from the plasma is found to be localized near the X-point of this RMP during plasma detachment which is confirmed both by the EMC3-EIRENE edge impurity transport code and experiments. This agreement motivates the establishment of a comparison between the results from the transport model and InfraRed imaging Video Bolometer (IRVB) experiments. A synthetic instrument has been developed which can simulate the radiation by tracing the sight lines through the three dimensional carbon impurity radiation results of the EMC3-EIRENE, giving a synthetic image. These synthetic images can be compared with the IRVB image obtained experimentally. Such a comparison is attempted here for two IRVBs installed on LHD for the data from the 2012 and 2013 experimental campaigns. The comparison reveals a fair amount of qualitative agreement but quantitative disagreement among both the approaches. Probable causes for the disagreement are discussed and corrective measures are suggested.

Keywords

IRVB, plasma detachment, radiation localization, resonant magnetic perturbation, synthetic diagnostic, edge transport model EMC3-EIRENE

DOI: 10.1585/pfr.9.3402064

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References

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This paper may be cited as follows:

Shwetang N. PANDYA, Byron J. PETERSON, Masahiro KOBAYASHI, Kiyofumi MUKAI, Ryuichi SANO, Hirohiko TANAKA, Suguru MASUZAKI and LHD Experiment Group, Plasma Fusion Res. 9, 3402064 (2014).