Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Numerical modeling of cosmic-ray transport in the heliosphere and
  interpretation of the proton-to-helium ratio in Solar Cycle 24   Thanks to space-borne experiments of cosmic-ray (CR) detection, such as the
AMS and PAMELA missions in low-Earth orbit, or the Voyager-1 spacecraft in the
interstellar space, a large collection of multi-channel and time-resolved CR
data has become available. Recently, the AMS experiment has released new
precision data, on the proton and helium fluxes in CRs, measured on monthly
basis during its first six years of mission. The AMS data reveal a remarkable
long-term behavior in the temporal evolution of the proton-to-helium ratio at
rigidity $R = p/Z <$ 3 GV. As we have argued in a recent work, such a behavior
may reflect the transport properties of low-rigidity CRs in the inteplanetary
space. In particular, it can be caused by mass/charge dependence of the CR
diffusion coefficient. In this paper, we present our developments in the
numerical modeling of CR transport in the Milky Way and in the heliosphere.
Within our model, and with the help of approximated analytical solutions, we
describe in details the relations between the properties of CR diffusion and
the time-dependent evolution of the proton-to-helium ratio.

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The categories of this paper are: supr-con
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
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The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg