Plasma and Fusion Research

Volume 20, 2402009 (2025)

Regular Articles


EUV Spectra of W13+ Ions in the Large Helical Device: Recent Progress in Observation of Tungsten Ions in Low to Intermediate Charge State Range for Fusion Plasma Diagnostics
Tetsutarou OISHI1), Ryota NISHIMURA1), Izumi MURAKAMI2,3), Daiji KATO2,4), Hiroyuki A. SAKAUE2), Motoshi GOTO2,3), Yasuko KAWAMOTO2,3), Tomoko KAWATE2,3), Nobuyuki NAKAMURA5), Hiroyuki TAKAHASHI1) and Kenji TOBITA1)
1)
Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2 Aobayama, Sendai 980-8579, Japan
2)
National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki 509-5292, Japan
3)
Graduate Institute for Advanced Studies, SOKENDAI, 322-6 Oroshi-cho, Toki 509-5292, Japan
4)
Interdisciplinary Graduate School of Engineering and Sciences, Kyushu University, Kasuga 816-8580, Japan
5)
Institute for Laser Science, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu 182-8585, Japan
(Received 31 July 2024 / Accepted 10 October 2024 / Published 22 January 2025)

Abstract

Spectroscopic studies of emissions released from tungsten ions combined with a pellet injection technique have been conducted in the Large Helical Device for contribution to the tungsten transport study in tungsten divertor fusion devices and for expansion of the experimental database of tungsten line emissions. Emission lines were explored for the observation of low to intermediate charge states in the range of W10+ to W20+, and the line spectra of W13+ were observed for the first time in fusion plasma experiments. The wavelengths of the observed W13+ lines were 243.1 Å, 247.6 Å, 248.3 Å, and 249.1Å in the extreme ultraviolet wavelength range, and all of them were emission from the 4f 135s2 - 4f 135s5p transitions.


Keywords

plasma spectroscopy, extreme ultraviolet, magnetically confined fusion, impurity transport, tungsten ions in low charge states

DOI: 10.1585/pfr.20.2402009


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