Electron density calculation based on Stark broadening of D Balmer line from detached plasma in EAST tungsten divertor

Feng XU (徐峰); Fang DING (丁芳); Xiahua CHEN (陈夏华); Liang WANG (王亮); Jichan XU (许吉禅); Zhenhua HU (胡振华); Hongmin MAO (毛红敏); Guangnan LUO (罗广南); Zhongshi YANG (杨钟时); Jingbo CHEN (陈竞博); Kedong LI (李克栋)

doi:10.1088/2058-6272/aad226

Plasma Science and Technology > 2018 > 20(10): 105102. > DOI: 10.1088/2058-6272/aad226

Feng XU (徐峰), Fang DING (丁芳), Xiahua CHEN (陈夏华), Liang WANG (王亮), Jichan XU (许吉禅), Zhenhua HU (胡振华), Hongmin MAO (毛红敏), Guangnan LUO (罗广南), Zhongshi YANG (杨钟时), Jingbo CHEN (陈竞博), Kedong LI (李克栋). Electron density calculation based on Stark broadening of D Balmer line from detached plasma in EAST tungsten divertor[J]. Plasma Science and Technology, 2018, 20(10): 105102. DOI: 10.1088/2058-6272/aad226

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Electron density calculation based on Stark broadening of D Balmer line from detached plasma in EAST tungsten divertor

¹ Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People’s Republic of China
² University of Science and Technology of China, Hefei 230026, People’s Republic of China

Funds: This work was supported by National Key Research and Development Program of China (No. 2017YFA0402500) and National Natural Science Foundation of China (Nos. 11575243, 11605238, and 11575242).

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Received Date: February 19, 2018

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Abstract

Abstract

The electron density within the volume of the tungsten divertor of the Experimental Advanced Superconducting Tokamak (EAST) is calculated based on D_ε line (396.9 nm) Stark broadening (SB) measurements. The quasistatic approximation is employed in the SB calculation of the D_ε line. The influences of other broadening mechanisms on the calculation error of electron density have been evaluated. The SB method is applied to the study of spatial distribution and time evolution of the electron density in the W divertor. Two electron density bands are observed in the detached divertor plasma during an L-mode discharge sustained by low hybrid wave (LHW) heating, which could be related to the striated particle flux distribution induced by LHW. After the onset of detachment, the upper electron density band corresponding to outer strike point firstly increases then decreases, while the lower density band corresponding to striated particle flux increases continually although the electron densities from Langmuir Probes at the divertor plate keep a descending trend. This could indicate a downward movement of the radiation region that approximately moves along the magnetic field lines after the onset of detachment.
- Stark broadening,
- electron density,
- detachment

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References (24)

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