Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wakefield acceleration in atmospheric plasmas: a possible source of MeV
  electrons   Intense electromagnetic pulses interacting with a plasma can create a wake of
plasma oscillations. Electrons trapped in such oscillations can be accelerated
under certain conditions to very high energies. We study the conditions for the
wakefield acceleration to produce MeV electrons in atmospheric plasmas. This
mechanism may explain the origin of MeV or runaway electrons needed in the
current theories for the production of Terrestrial Gamma ray Flashes.

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The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph