Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasi-monoenergetic electron beams from laser plasma acceleration using
  nitrogen gas jet   An experimental investigation on laser plasma acceleration of electrons has
been carried out using 3 TW, 45 fs duration titanium sapphire laser pulse
interaction with nitrogen gas jet at intensity of 2x10^18 W/cm^2. We have
observed stable generation of well collimated electron beam with divergence and
pointing variation ~ 10 mrad from the nitrogen gas jet plasma at an optimum
plasma density around 3x10^19 cm^-3. The energy spectrum of the electron beam
was quasi-monoenergetic with average peak energy and charge around 25 MeV and
30 pC respectively. The results will be useful for better understanding and
control of ionization injection and laser wakefield acceleration of electrons
in high-Z gases and also to develop practical laser wakefield accelerators for
various applications including injectors for high energy accelerators.

16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph