Impact of a large density gradient on linear and nonlinear edgelocalized mode simulations
Here, the impact of a large density gradient on edgelocalized modes (ELMs) is studied linearly and nonlinearly by employing both twofluid and gyrofluid simulations. In twofluid simulations, the ion diamagnetic stabilization on highn modes disappears when the large density gradient is taken into account. But gyrofluid simulations show that the finite Larmor radius (FLR) effect can effectively stabilize highn modes, so the ion diamagnetic effect alone is not sufficient to represent the FLR stabilizing effect. We further demonstrate that additional gyroviscous terms must be kept in the twofluid model to recover the linear results from the gyrofluid model. Nonlinear simulations show that the density variation significantly weakens the E × B shearing at the top of the pedestal and thus leads to more energy loss during ELMs. The turbulence spectrum after an ELM crash is measured and has the relation of $$P(k_{z})\propto k_{z}^{3.3}$$ .
 Authors:

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 Peking Univ., Beijing (People's Republic of China); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Chinese Academy of Sciences, Hefei (People's Republic of China)
 National Fusion Research Institute, Daejeon (Republic of Korea)
 Publication Date:
 Report Number(s):
 LLNLJRNL630194
Journal ID: ISSN 00295515
 Grant/Contract Number:
 AC5207NA27344
 Type:
 Accepted Manuscript
 Journal Name:
 Nuclear Fusion
 Additional Journal Information:
 Journal Volume: 53; Journal Issue: 11; Journal ID: ISSN 00295515
 Publisher:
 IOP Science
 Research Org:
 Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
 Sponsoring Org:
 USDOE
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION
 OSTI Identifier:
 1357326
Xi, P. W., Xu, X. Q., Xia, T. Y., Nevins, W. M., and Kim, S. S.. Impact of a large density gradient on linear and nonlinear edgelocalized mode simulations. United States: N. p.,
Web. doi:10.1088/00295515/53/11/113020.
Xi, P. W., Xu, X. Q., Xia, T. Y., Nevins, W. M., & Kim, S. S.. Impact of a large density gradient on linear and nonlinear edgelocalized mode simulations. United States. doi:10.1088/00295515/53/11/113020.
Xi, P. W., Xu, X. Q., Xia, T. Y., Nevins, W. M., and Kim, S. S.. 2013.
"Impact of a large density gradient on linear and nonlinear edgelocalized mode simulations". United States.
doi:10.1088/00295515/53/11/113020. https://www.osti.gov/servlets/purl/1357326.
@article{osti_1357326,
title = {Impact of a large density gradient on linear and nonlinear edgelocalized mode simulations},
author = {Xi, P. W. and Xu, X. Q. and Xia, T. Y. and Nevins, W. M. and Kim, S. S.},
abstractNote = {Here, the impact of a large density gradient on edgelocalized modes (ELMs) is studied linearly and nonlinearly by employing both twofluid and gyrofluid simulations. In twofluid simulations, the ion diamagnetic stabilization on highn modes disappears when the large density gradient is taken into account. But gyrofluid simulations show that the finite Larmor radius (FLR) effect can effectively stabilize highn modes, so the ion diamagnetic effect alone is not sufficient to represent the FLR stabilizing effect. We further demonstrate that additional gyroviscous terms must be kept in the twofluid model to recover the linear results from the gyrofluid model. Nonlinear simulations show that the density variation significantly weakens the E × B shearing at the top of the pedestal and thus leads to more energy loss during ELMs. The turbulence spectrum after an ELM crash is measured and has the relation of $P(k_{z})\propto k_{z}^{3.3}$ .},
doi = {10.1088/00295515/53/11/113020},
journal = {Nuclear Fusion},
number = 11,
volume = 53,
place = {United States},
year = {2013},
month = {9}
}