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Title: Gyrokinetic simulation study of magnetic island effects on neoclassical physics and micro-instabilities in a realistic KSTAR plasma

Abstract

Here, we perform gyrokinetic simulations to study the effects of a stationary magnetic island on neoclassical flow and micro-instability in a realistic KSTAR plasma condition. Through the simulations, we aim to analyze a recent KSTAR experiment, which was to measure the details of poloidal flow and fluctuation around a stationary (2, 1) magnetic island [M. J. Choi et al., Nucl. Fusion 57, 126058 (2017)]. From the simulations, it is found that the magnetic island can significantly enhance the equilibrium E x B flow. The corresponding flow shearing is strong enough to suppress a substantial portion of ambient micro-instabilities, particularly ∇T e-driven trapped electron modes. This implies that the enhanced E x B flow can sustain a quasi-internal transport barrier for T e in an inner region neighboring the magnetic island. The enhanced E x B flow has a (2, 1) mode structure with a finite phase shift from the mode structure of the magnetic island. It is shown that the flow shear and the fluctuation suppression patterns implied from the simulations are consistent with the observations on the KSTAR experiment.

Authors:
 [1];  [2]; ORCiD logo [3]; ORCiD logo [2]; ORCiD logo [2];  [4];  [3];  [3]
  1. National Fusion Research Inst. (NFRI), Daejeon (Korea, Republic of); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. National Fusion Research Inst. (NFRI), Daejeon (Korea, Republic of)
  4. Rensselaer Polytechnic Inst., Troy, NY (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); Simmetrix Inc., Clifton Park, NY (United States)
OSTI Identifier:
1438032
Alternate Identifier(s):
OSTI ID: 1436912; OSTI ID: 1459559
Grant/Contract Number:  
SC0013919; AC02-09CH11466; NFRI-EN1841-4; AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma instabilities; plasma flows; classical mechanics; plasma confinement

Citation Formats

Kwon, Jae-Min, Ku, S., Choi, M. J., Chang, C. S., Hager, R., Yoon, E. S., Lee, H. H., and Kim, H. S. Gyrokinetic simulation study of magnetic island effects on neoclassical physics and micro-instabilities in a realistic KSTAR plasma. United States: N. p., 2018. Web. doi:10.1063/1.5027622.
Kwon, Jae-Min, Ku, S., Choi, M. J., Chang, C. S., Hager, R., Yoon, E. S., Lee, H. H., & Kim, H. S. Gyrokinetic simulation study of magnetic island effects on neoclassical physics and micro-instabilities in a realistic KSTAR plasma. United States. doi:10.1063/1.5027622.
Kwon, Jae-Min, Ku, S., Choi, M. J., Chang, C. S., Hager, R., Yoon, E. S., Lee, H. H., and Kim, H. S. Tue . "Gyrokinetic simulation study of magnetic island effects on neoclassical physics and micro-instabilities in a realistic KSTAR plasma". United States. doi:10.1063/1.5027622. https://www.osti.gov/servlets/purl/1438032.
@article{osti_1438032,
title = {Gyrokinetic simulation study of magnetic island effects on neoclassical physics and micro-instabilities in a realistic KSTAR plasma},
author = {Kwon, Jae-Min and Ku, S. and Choi, M. J. and Chang, C. S. and Hager, R. and Yoon, E. S. and Lee, H. H. and Kim, H. S.},
abstractNote = {Here, we perform gyrokinetic simulations to study the effects of a stationary magnetic island on neoclassical flow and micro-instability in a realistic KSTAR plasma condition. Through the simulations, we aim to analyze a recent KSTAR experiment, which was to measure the details of poloidal flow and fluctuation around a stationary (2, 1) magnetic island [M. J. Choi et al., Nucl. Fusion 57, 126058 (2017)]. From the simulations, it is found that the magnetic island can significantly enhance the equilibrium E x B flow. The corresponding flow shearing is strong enough to suppress a substantial portion of ambient micro-instabilities, particularly ∇Te-driven trapped electron modes. This implies that the enhanced E x B flow can sustain a quasi-internal transport barrier for Te in an inner region neighboring the magnetic island. The enhanced E x B flow has a (2, 1) mode structure with a finite phase shift from the mode structure of the magnetic island. It is shown that the flow shear and the fluctuation suppression patterns implied from the simulations are consistent with the observations on the KSTAR experiment.},
doi = {10.1063/1.5027622},
journal = {Physics of Plasmas},
number = 5,
volume = 25,
place = {United States},
year = {2018},
month = {5}
}

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