Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Laboratory gamma-ray pulsar   The mechanism by which gamma-ray pulsars shine might be reproducible in a
laboratory. This claim is supported by three observations: (i) properly
focusing a few PW optical laser gives an electromagnetic field in the so-called
Aristotelian regime, when a test electron is radiation-overdamped; (ii) the
Goldreich-Julian number density of this electromagnetic field (the number
density of elementary charges needed for a nearly full conversion of optical
power into gamma-rays) is of order the electron number density in a solid;
(iii) above about $50$PW, the external source of electrons is not needed --
charges will be created by a pair production avalanche.

32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas