Plasma and Fusion Research

Volume 20, 2402005 (2025)

Regular Articles


Investigation of Tungsten Unresolved Transition Array Spectrum around 300Å for Fusion Plasma Diagnostics
Ryota NISHIMURA1), Tetsutarou OISHI1), Izumi MURAKAMI2,3), Daiji KATO2,4), Hiroyuki A. SAKAUE2,3), Gupta SHIVAM5), Hayato OHASHI6), Motoshi GOTO2,3), Yasuko KAWAMOTO2,3), Tomoko KAWATE2,3), Chihiro SUZUKI2,3), Hiroyuki TAKAHASHI1) and Kenji TOBITA1)
1)Department of Quantum Science and Energy Engineering, Tohoku University, Sendai 980-8579, Japan
2)National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
3)The Graduate University for Advanced Studies, SOKENDAI, Toki 509-5292, Japan
4)Interdisciplinary Graduate School of Engineering Sciences, Kyusyu University, Kasuga 816-8580, Japan
5)Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan
6)Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-8555, Japan
(Received 24 July 2024 / Accepted 18 September 2024 / Published 22 January 2025)

Abstract

Tungsten spectroscopic studies have attracted much attention, because tungsten will be used as a plasma-facing component in ITER and future DEMO reactors. However, spectral line data of tungsten ions in low to intermediate charge states, such as W8+-W26+, is still lacking. To accumulate spectral line data of W8+-W26+, it is very important to identify the charge state and transition of Unresolved Transition Array (UTA) spectrum, as well as discrete line spectrum. In this study, we investigated electron temperature dependence of a UTA spectrum around 300Å for an advanced understanding of spectral line shape. As a result, the UTA spectrum contains W17+-W27+ and emission line from 5s-5p transition and its satellite line from 5s2-5s5p transition are strongly emitted. It was suggested that the UTA spectrum around 300Å will be useful for diagnostics of ITER edge plasma.


Keywords

Tungsten, EUV spectrum, spectroscopy, large helical device, flexible atomic code

DOI: 10.1585/pfr.20.2402005


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