Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generation of GeV protons from 1 PW laser interaction with near critical
  density targets   The propagation of ultra intense laser pulses through matter is connected
with the generation of strong moving magnetic fields in the propagation channel
as well as the formation of a thin ion filament along the axis of the channel.
Upon exiting the plasma the magnetic field displaces the electrons at the back
of the target, generating a quasistatic electric field that accelerates and
collimates ions from the filament. Two-dimensional Particle-in-Cell simulations
show that a 1 PW laser pulse tightly focused on a near-critical density target
is able to accelerate protons up to an energy of 1.3 GeV. Scaling laws and
optimal conditions for proton acceleration are established considering the
energy depletion of the laser pulse.

26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph