Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Production and dynamics of positrons in ultrahigh intensity laser-foil
  interactions   The electron-positron pair production accompanying interaction of a
circularly polarized laser pulse with a foil is studied for laser intensities
higher than $10^{24}$W cm$^{-2}$. The laser energy penetrates into the foil due
to the effect of the relativistic hole-boring. It is demonstrated that the
electron-positron plasma is produced as a result of quantum-electrodynamical
cascading in the field of the incident and reflected laser light in front of
the foil. The incident and reflected laser light makes up the circularly
polarized standing wave in the reference frame of the hole-boring front and the
pair density peaks near the nodes and antinodes of the wave. A model based on
the particle dynamics with radiation reaction effect near the magnetic nodes is
developed. The model predictions are verified by 3D PIC-MC simulations.

36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat