Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Plasmoid Instability in High-Lundquist-Number Magnetic Reconnection   Our understanding of magnetic reconnection in resistive magnetohydrodynamics
has gone through a fundamental change in recent years. The conventional wisdom
is that magnetic reconnection mediated by resistivity is slow in laminar high
Lundquist ($S$) plasmas, constrained by the scaling of the reconnection rate
predicted by Sweet-Parker theory. However, recent studies have shown that when
$S$ exceeds a critical value $\sim10^{4}$, the Sweet-Parker current sheet is
unstable to a super-Alfv\'enic plasmoid instability, with a linear growth rate
that scales as $S^{1/4}$. In the fully developed statistical steady state of
two-dimensional resistive magnetohydrodynamic simulations, the normalized
average reconnection rate is approximately 0.01, nearly independent of $S$, and
the distribution function $f(\psi)$ of plasmoid magnetic flux $\psi$ follows a
power law $f(\psi)\sim\psi^{-1}$. When Hall effects are included, the plasmoid
instability may trigger onset of Hall reconnection even when the conventional
criterion for onset is not satisfied. The rich variety of possible reconnection
dynamics is organized in the framework of a phase diagram.

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The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
11
The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: mtrl-th
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The categories of this paper are: stat
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph