Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron Acceleration in the Crab Nebula   We study electron and positron acceleration at the termination shock of a
striped pulsar wind. Drift motion along the shock surface keeps either
electrons or positrons -but not both, close to the equatorial plane of the
pulsar, where they are accelerated by the first-order Fermi process. Their
energy spectrum is a power law, and both the X-ray flux and photon index of the
Crab Nebula, as measured by NuSTAR, can be reproduced for sufficiently large
downstream turbulence levels. The implication that one sign of charge is
preferentially accelerated in pulsar wind nebulae is potentially important for
the interpretation of the positron fraction in cosmic-rays.

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The categories of this paper are: comp-gas
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
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The categories of this paper are: hep-th
3
The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-lat
1
The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc