Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffusion of Cosmic Rays in a Multiphase Interstellar Medium Swept-Up by
  a Supernova Remnant Blast Wave   Supernova remnants (SNRs) are one of the most energetic astrophysical events
and are thought to be the dominant source of Galactic cosmic rays (CRs). A
recent report on observations from the Fermi satellite has shown a signature of
pion decay in the gamma-ray spectra of SNRs. This provides strong evidence that
high-energy protons are accelerated in SNRs. The actual gamma-ray emission from
pion decay should depend on the diffusion of CRs in the interstellar medium. In
order to quantitatively analyse the diffusion of high-energy CRs from
acceleration sites, we have performed test particle numerical simulations of CR
protons using a three-dimensional magnetohydrodynamics (MHD) simulation of an
interstellar medium swept-up by a blast wave. We analyse the diffusion of CRs
at a length scale of order a few pc in our simulated SNR, and find the
diffusion of CRs is precisely described by a Bohm diffusion, which is required
for efficient acceleration at least for particles with energies above 30 TeV
for a realistic interstellar medium. Although we find the possibility of a
superdiffusive process (travel distance proportional to t^0.75) in our
simulations, its effect on CR diffusion at the length scale of the turbulence
in the SNR is limited.

21
The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
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The categories of this paper are: econ
8
The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
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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: cmp-lg
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The categories of this paper are: plasm-ph