Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the effective particle acceleration in the paraboloidal magnetic
  field   The problem of the efficiency of particle acceleration for parabolic poloidal
magnetic field is considered within the approach of steady axisymmetric MHD
flow. For the large Michel magnetization parameter it is possible to linearize
the stream equation near the force-free solution and to solve the problem
self-consistently as was done by Beskin, Kuznetsova and Rafikov (1998) for
monopole magnetic field. It is shown that on the fast magnetosonic surface the
particle Lorentz factor does not exceed the standard value. On the other hand,
in the supersonic region the Lorentz factor grows linearly with the distance
from the rotational axis, reaching almost its maximal value. This corresponds
to almost the full conversion of the Poynting energy flux into the particle
kinetic one.

31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int