Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stationary Bernstein-Greene-Kruskal structures in a current carrying
  relativistic cold plasma   Nonlinear stationary structures formed in a cold plasma with immobile ions in
the presence of a relativistic electron current beam have been investigated
analytically in the collisionless limit. These are cold plasma version of the
relativistic Berstein-Greene-Kruskal (BGK) waves. The structure profile is
governed by the ratio of maximum electrostatic field energy density to the
relativistic kinetic energy density of the electron beam, {\it i.e.},
$\kappa_{R} = E_{m}/ (8 \pi n_{0} (\gamma_{0}-1)m_{0} c^{2})^{1/2}$, where
$E_{m}$ is the maximum electric field associated with the nonlinear structure
and $\gamma_{0}$ is the Lorentz factor associated with the beam velocity. It is
found that, in the linear limit, {\it i.e.}, $\kappa_{R} \ll
1/\sqrt{\gamma_{0}}$, the fluid variables, {\it viz}, density, electric field,
and velocity vary harmonically in space. In the range $0 < \kappa_{R} \leq
1/\sqrt{\gamma_{0}}$, the fluid variables exhibit an-harmonic behavior. For
values of $\kappa_{R} > 1/\sqrt{\gamma_{0}}$, the electric field shows finite
discontinuities at specific spatial locations indicating the formation of
negatively charged planes at these locations.

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The categories of this paper are: gr-qc
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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: cond-mat
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The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin