Plasma and Fusion Research

Volume 20, 2402010 (2025)

Regular Articles


The Observation of Tungsten Unresolved Transition Arrays Spectra at High Electron Temperature in Experimental Advanced Superconducting Tokamak (EAST) Plasma
Yunxin CHENG1), Ling ZHANG1), Shigeru MORITA2), Ailan HU1), Chengxi ZHOU1), Darío MITNIK3), Wenmin ZHANG1,4), Fengling ZHANG1,4), Jiuyang MA1,4), Zhengwei LI1,5), Yiming CAO1,5) and Haiqing LIU1)
1)
Institute of plasma physics, Chinese Academy of Sciences, Hefei 230031, China
2)
National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
3)
Instituto de Astronomía y Física del Espacio (CONICET-Universidad de Buenos Aires), Buenos Aires 1428, Argentina
4)
University of Science and Technology of China, Hefei 230026, China
5)
Anhui University, Hefei 230601, China
(Received 31 July 2024 / Accepted 15 October 2024 / Published 22 January 2025)

Abstract

To optimize the plasma performance of fusion devices using tungsten plasma-facing components (PFCs), it is crucial to study the transport of tungsten impurities. This work focuses on the observation of line emissions from various charge states of tungsten ions in high-temperature plasmas utilizing Extreme Ultraviolet (EUV) spectrometers. Line emissions from W26+-W32+ ions are observed in the 45-55Å band at electron temperatures below 2.0 keV, while line emissions from W34+-W45+ ions appear in the 55-70Å band at electron temperatures above 3.0 keV. Additionally, radial profiles of W-UTA spectra in plasma with different electron temperature show that as the electron temperature decreases from 5.0 keV to 3.0 keV, the peak position of W26+-W32+ ions move inward from ρ∼0.5 to ρ∼0.2. The line intensity profiles of W42+-W45+ ions accumulate within a narrow region of plasma core, specifically at ρ < 0.4. This study provides essential experimental data to support further research on tungsten impurity transport, control of tungsten content, and the enhancement of plasma performance.


Keywords

EAST tokamak, high temperature plasma, impurity ion, extreme ultraviolet spectroscopy, tungsten spectra

DOI: 10.1585/pfr.20.2402010


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