Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bright betatron radiation from direct-laser-accelerated electrons at
  moderate relativistic laser intensity   Direct laser acceleration (DLA) of electrons in a plasma of near critical
electron density (NCD) and associated synchrotron-like radiation are discussed
for moderate relativistic laser intensity (the normalized laser amplitude $a_0$
$\leq$ 4.3) and ps-long pulse. This regime is typical for kJ PW-class laser
facilities designed for high energy density research. Currently, in experiments
at the PHELX laser it was demonstrated that interaction of 10$^{19}$ W/cm$^{2}$
sub-ps laser pulse with sub-mm long NCD plasma results in generation of
high-current well-directed super-ponderomotive electrons with effective
temperature that is 10$\times$ higher than the ponderomotive potential [O.
Rosmej et al., PPCF 62, 115024 (2020)]. Three-dimensional Particle-In-Cell
simulations provided a good agreement with the measured electron energy
distribution and were used in the current work to study synchrotron radiation
of the DLA accelerated electrons. The resulting x-ray spectrum with a critical
energy of 5 keV reveals an ultra-high photon number of 7$\times$10$^{11}$ in
the 1-30 keV photon energy range at the focused laser energy of 20 J. Numerical
simulations of a betatron x-ray phasecontrast imaging based on the DLA process
for the parameters of a PHELIX laser is presented. The results are of interest
for applications in high energy density (HED) experiments, which require a
picosecond x-ray pulse and a high photon flux.

8
The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol