Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio emission and particle acceleration in plerionic supernova remnants   Plerionic supernova remnants exhibit radio emission with remarkably flat
spectral indices ranging from $\alpha=0.0$ to $\alpha=-0.3$. The origin of very
hard particle energy distributions still awaits an explanation, since shock
waves generate particle distributions with synchrotron spectra characterized by
$\alpha\le-0.5$. Acceleration of high energy leptons in magnetohydrodynamic
turbulence instead may be responsible for the observed hard spectra. This
process is studied by means of relativistic test particle calculations using
electromagnetic fields produced by three-dimensional simulations of resistive
magnetohydrodynamical turbulence. The particles receive power-law energy
spectra $N(\gamma)\propto \gamma^{-s}$ with $s$ ranging from 1.2 to 1.6, i.e.
particle spectra that are required to explain the radio emission of plerions.

19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th