Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High Repetition-Rate Wakefield Electron Source Generated by
  Few-millijoule, 30 femtosecond Laser Pulses on a Density Downramp   We report on an experimental demonstration of laser wakefield electron
acceleration using a sub-TW power laser by tightly focusing 30-fs laser pulses
with only 8 mJ pulse energy on a 100 \mu m scale gas target. The experiments
are carried out at an unprecedented 0.5 kHz repetition rate, allowing "real
time" optimization of accelerator parameters. Well-collimated and stable
electron beams with a quasi-monoenergetic peak in excess of 100 keV are
measured. Particle-in-cell simulations show excellent agreement with the
experimental results and suggest an acceleration mechanism based on electron
trapping on the density downramp, due to the time varying phase velocity of the
plasma waves.

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The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph