Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Estimation of the release time of solar energetic particles near the Sun   This paper investigates the onset time of Solar Energetic Particle (SEP)
events with numerical simulations, and analyses the accuracy of the Velocity
Dispersion Analysis (VDA) method. Using a 3-dimensional focused transport
model, we calculate the fluxes of protons observed in the ecliptic at 1 AU in
the energy range between 10 MeV and 80 MeV. In particular, three models are
used to describe different SEP sources produced by flare or coronal shock, and
the effects of particle perpendicular diffusion in the interplanetary space are
also studied. We have the following findings: When the observer is disconnected
from the source, the effects of perpendicular diffusion in the interplanetary
space and particles propagating in the solar atmosphere have significant
influence on the VDA results. As a result, although the VDA method is valid
with impulsive source duration, low background, and weak scattering in the
interplanetary space or fast diffusion in the solar atmosphere, the method is
not valid with gradual source duration, high background, or strong scattering.

22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int