Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gamma-Ray Flash Generation in Irradiating Thin Foil Target by Single
  Cycle Tightly Focused Extreme Power Laser Pulse   We present a regime where an ultra-intense laser pulse interacting with a
foil target results in high $\gamma$-photon conversion efficiency, obtained via
three-dimensional quantum-electrodynamics particle-in-cell simulations. A
single-cycle laser pulse is used under the tight-focusing condition for
obtaining the $\mathrm{\lambda}^3$ regime. The simulations employ a radially
polarized laser as it results in higher $\gamma$-photon conversion efficiency
compared to both azimuthal and linear polarizations. A significant fraction of
the laser energy is transferred to positrons, while a part of the
electromagnetic wave escapes the target as attosecond single-cycle pulses.

18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con