Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase space consideration of low energy electron injection for Direct
  Laser Acceleration   Feasibility of ionization injection for Direct Laser Acceleration (DLA) of
electrons up to hundreds of MeV was studied analytically. Criteria for
effective injection determining range of background and in-channel plasma
parameters, laser intensity, etc. were found using phase portraits of the
system deduced from the simplified analytical model. The found optimal
trajectory in the phase space corresponds to the electron with low (few eV)
initial energy experiencing $\sim$10$^9$ times energy gain. For this to occur,
electron density should be a few percent of the critical density, while the
in-channel electron density should be $\sim$3 times lower. The analytically
obtained dependence of the energy gain on the initial electron longitudinal and
transverse momenta corresponds well to the results of exact numerical
simulations of an electron motion in the plasma channel. Developed approach can
form the basis for further studies of electron injection in DLA varying plasma
and laser parameters as well as initial electron energies.

31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess