Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Early propagation of energetic particles across the mean field in
  turbulent plasmas   Propagation of energetic particles across the mean field direction in
turbulent magnetic fields is often described as spatial diffusion. Recently, it
has been suggested that initially the particles propagate systematically along
meandering field lines, and only later reach the time-asymptotic diffusive
cross-field propagation. In this paper, we analyse cross-field propagation of
1--100 MeV protons in composite 2D-slab turbulence superposed on a constant
background magnetic field, using full-orbit particle simulations, to study the
non-diffusive phase of particle propagation with a wide range of turbulence
parameters. We show that the early-time non-diffusive propagation of the
particles is consistent with particle propagation along turbulently meandering
field lines. This results in a wide cross-field extent of the particles already
at the initial arrival of particles to a given distance along the mean field
direction, unlike when using spatial diffusion particle transport models. The
cross-field extent of the particle distribution remains constant for up to tens
of hours in turbulence environment consistent with the inner heliosphere during
solar energetic particle events. Subsequently, the particles escape from their
initial meandering field lines, and the particle propagation across the mean
field reaches time-asymptotic diffusion. Our analysis shows that in order to
understand solar energetic particle event origins, particle transport modelling
must include non-diffusive particle propagation along meandering field lines.

32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph