Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear MHD simulation of core plasma collapse events in stellarators   The core collapse events observed in a stellarator experiment are studied by
a three-dimensional nonlinear MHD simulations. In the low magnetic shear
configuration like the Wendelstein 7-X, the rotational transform profile is
very sensitive to the toroidal current density. The 3D equilibrium with
localized toroidal current density is studied. If the toroidal current density
follows locally in the middle of the plasma minor radius, the rotational
transform is also changed locally. Sometimes, the magnetic topology changes due
to appearing the magnetic island. The nonlinear behaviors of the MHD
instability are studied by a full three-dimensional nonlinear MHD code. It was
found that a following sequence. At first, the high-n ballooning-type mode
structure appears in the plasma core, and then the mode linearly grows. The
high-n ballooning modes nonlinearly couple and saturate. The mode structure
changes to the low-n mode. In that phase, the magnetic field structure becomes
strongly stochastic into the plasma core due to the nonlinear coupling.
Finally, the plasma pressure diffuses along the stochastic field lines, and
then the core plasma pressure drops. This is an important results to interpret
the core collapse event by strong nonlinear coupling.

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The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
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The categories of this paper are: math
28
The categories of this paper are: alg-geom