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approvedabs_ppr.pdf2016-02-15 16:24:31Ping Zhu


Author: Ping Zhu
Requested Type: Poster
Submitted: 2016-02-15 16:23:40

Co-authors: Xingting Yan, Wenlong Huang

Contact Info:
University of Science and Technology of China
96 Jinzhai Road
Hefei,   230026

Abstract Text:
Resonant magnetic perturbations (RMPs) are believed to play important
roles in suppressing and mitigating the edge localized modes (ELMs) in
tokamak experiments. To understand the effects of RMPs on the
properties of tokamak edge pedestal plasma, linear plasma response has
often been assumed in calculations and interpretations. In this work,
we compare linear and nonlinear calculations on the plasma responses
of the edge pedestal region to RMPs in a circular-shaped limiter
tokamak, using both a reduced MHD model in theory and a full MHD model
with anisotropic heat transport implemented in the NIMROD code. A
low-$n$ RMP with a single helicity is imposed as the boundary
condition at the tokamak wall location, where $n$ is the toroidal mode
number. Plasma responses to RMPs are obtained through solving and
analyzing the steady states of the linear and the nonlinear MHD system
subject to the RMP boundary condition. For a given RMP, it is found
that there can be substantial difference in magnitude between the
linear and nonlinear plasma response in the highly resistive
regime. Such a difference tends to diminish as the resisitivy reduces
toward the ideal regime. Linear and nonlinear plasma responses can be
also quite different on the resonant flux surfaces located near the
pedestal foot. As the resonant surface moves inward the pedestal, the
difference can become insignificant. The underlying physics for the
dependence of the difference in linear and nonlinear plasma responses
on the resistivity and the resonant location will be discussed.

Supported by National Magnetic Confinement Fusion Science Program of China Grant Nos. 2014GB124002 and 2015GB101004, U.S. Department of Energy Grant Nos. DE-FG02-86ER53218 and DE-FC02-08ER54975.