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Experimental and simulation study of impurity transport response to RMPs in RF-heated H-mode plasmas at EAST

Part of: Focus on Fusion

Published online by Cambridge University Press:  29 March 2021

Germán Vogel Open the ORCID record for Germán Vogel [Opens in a new window] ,
Hongming Zhang ,
Yongcai Shen ,
Shuyu Dai Open the ORCID record for Shuyu Dai [Opens in a new window] ,
Youwen Sun ,
Juan Huang ,
Shuai Gu ,
Jia Fu ,
Ruiji Hu  and
Jun Chen
...Show all authors
Germán Vogel
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China School of Nuclear Science and Technology, University of Science and Technology of China, Hefei230026, PR China
Hongming Zhang
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China
Yongcai Shen
Affiliation:
School of Physics and Materials Engineering, Hefei Normal University, Hefei230601, PR China
Shuyu Dai
Affiliation:
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian116024, PR China
Youwen Sun
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China
Juan Huang
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China
Shuai Gu
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China
Jia Fu
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China
Ruiji Hu
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China School of Nuclear Science and Technology, University of Science and Technology of China, Hefei230026, PR China
Jun Chen
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China School of Nuclear Science and Technology, University of Science and Technology of China, Hefei230026, PR China
Xuewei Du
Affiliation:
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei230029, PR China
Qiuping Wang
Affiliation:
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei230029, PR China
Yi Yu
Affiliation:
School of Nuclear Science and Technology, University of Science and Technology of China, Hefei230026, PR China
Shifeng Mao
Affiliation:
School of Nuclear Science and Technology, University of Science and Technology of China, Hefei230026, PR China
Bo Lyu*
Affiliation:
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei230031, PR China
Minyou Ye*
Affiliation:
School of Nuclear Science and Technology, University of Science and Technology of China, Hefei230026, PR China
*
†Email addresses for correspondence: [email protected], [email protected]
†Email addresses for correspondence: [email protected], [email protected]
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Abstract

Spatial profiles of impurity emission measurements in the extreme ultraviolet (EUV) spectroscopic range in radiofrequency (RF)-heated discharges are combined with one-dimensional and three-dimensional transport simulations to study the effects of resonant magnetic perturbations (RMPs) on core impurity accumulation at EAST. The amount of impurity line emission mitigation by RMPs appears to be correlated with the ion Z for lithium, carbon, iron and tungsten monitored, i.e. stronger suppression of accumulation for heavier ions. The targeted effect on the most detrimental high-Z impurities suggests a possible advantage using RMPs for impurity control. Profiles of transport coefficients are calculated with the STRAHL one-dimensional impurity transport code, keeping $\nu /D$ fixed and using the measured spatial profiles of $\textrm{F}{\textrm{e}^{20 + }}$, $\textrm{F}{\textrm{e}^{21 + }}$ and $\textrm{F}{\textrm{e}^{22 + }}$ to disentangle the transport coefficients. The iron diffusion coefficient ${D_{\textrm{Fe}}}$ increases from $1.0- 2.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ to $1.5- 3.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ from the core region to the edge region $(\rho \gt 0.5)$ after the onset of RMPs. Meanwhile, an inward pinch of iron convective velocity ${\nu _{\textrm{Fe}}}$ decreases in magnitude in the inner core region and increases significantly in the outer confined region, simultaneously contributing to preserving centrally peaked $\textrm{Fe}$ profiles and exhausting the impurities. The ${D_{\textrm{Fe}}}$ and ${\nu _{\textrm{Fe}}}$ variations lead to reduced impurity contents in the plasma. The three-dimensional edge impurity transport code EMC3-EIRENE was also applied for a case of RMP-mitigated high-Z accumulation at EAST and compared to that of low-Z carbon. The exhaust of ${\textrm{C}^{6 + }}$ toward the scrape-off layer accompanying an overall suppression of heavier ${\textrm{W}^{30 + }}$ is observed when using RMPs.

Keywords

fusion plasmaplasma diagnosticsplasma simulation
Type
Research Article
Information
Journal of Plasma Physics , Volume 87 , Issue 2 , April 2021 , 905870213
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Copyright
Copyright © The Author(s), 2021. Published by Cambridge University Press

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