Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coherent forward stimulated Brillouin scattering of a spatially
  incoherent laser beam in a plasma and its effect on beam spray   A statistical model for forward stimulated Brillouin scattering (FSBS) is
developed for a spatially incoherent, monochromatic, laser beam propagating in
a plasma. A threshold for the average power in a speckle is found, well below
the self-focusing one, above which the laser beam spatial incoherence can not
prevent the coherent growth of FSBS. Three-dimensional simulations confirm its
existence and reveal the onset of beam spray above it. From these results, we
propose a new figure of merit for the control of the propagation through a
plasma of a spatially incoherent laser beam.

27
The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin