Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relativistic solitary waves modulating long laser pulses in plasmas   This article discusses the existence of solitary electromagnetic waves
trapped in a self-generated Langmuir wave and embedded in an infinitely long
circularly polarized electromagnetic wave propagating through a plasma. From
the mathematical point of view they are exact solutions of the 1-dimensional
relativistic cold fluid plasma model with nonvanishing boundary conditions.
Under the assumption of traveling wave solutions with velocity $V$ and vector
potential frequency $\omega$, the fluid model is reduced to a Hamiltonian
system. The solitary waves are homoclinic (grey solitons) or heteroclinic (dark
solitons) orbits to fixed points. By using a dynamical systems description of
the Hamiltonian system and a spectral method, we identify a great variety of
solitary waves, including asymmetric ones, discuss their disappearance for
certain parameter values, and classify them according to: (i) grey or dark
character, (ii) the number of humps of the vector potential envelope and (iii)
their symmetries. The solutions come in continuous families in the parametric
$V-\omega$ plane and extend up to velocities that approach the speed of light.
The stability of certain types of grey solitary waves is investigated with the
aid of particle-in-cell simulations that demonstrate their propagation for a
few tens of the inverse of the plasma frequency.

12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
18
The categories of this paper are: econ
2
The categories of this paper are: math
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas