Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modelling the Propagation of a Weak Fast-Mode MHD Shock Wave near a 2D
  Magnetic Null Point Using Nonlinear Geometrical Acoustics   We present the results of analytical modelling of fast-mode
magnetohydrodynamic wave propagation near a 2D magnetic null point. We consider
both a linear wave and a weak shock and analyse their behaviour in cold and
warm plasmas. We apply the nonlinear geometrical acoustics method based on the
Wentzel-Kramers-Brillouin approximation. We calculate the wave amplitude, using
the ray approximation and the laws of solitary shock wave damping. We find that
a complex caustic is formed around the null point. Plasma heating is
distributed in space and occurs at a caustic as well as near the null point due
to substantial nonlinear damping of the shock wave. The shock wave passes
through the null point even in a cold plasma. The complex shape of the wave
front can be explained by the caustic pattern.

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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
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The categories of this paper are: physics
1
The categories of this paper are: cs
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The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
10
The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex