Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffusion coefficient and radial gradient of galactic cosmic rays   We present the temporal changes of the diffusion coefficient K of galactic
cosmic rays (GCRs) at the Earth orbit calculated based on the experimental data
using two different methods. The first approach is based on the Parker
convection-diffusion approximation of GCR modulation [1]: i.e. K~Vr=dI where dI
is the variation of the GCR intensity measured by neutron monitors (NM),V is
the solar wind velocity and r is the radial distance. The second approach is
based on the interplanetary magnetic field (IMF) data. It was suggested that
parallel mean free path can be expressed in terms of B as in [2]-[4]. Using
data of the product of the parallel mean free path and radial gradient of GCR
calculated based on the GCR anisotropy data (Ahluwalia et al., this conference
ICRC 2013, poster ID: 487 [5]), we estimate the temporal changes of the radial
gradient of GCR at the Earth orbit. We show that the radial gradient exhibits a
strong solar cycle dependence (11-year variation) and a weak solar magnetic
cycle dependence (22-year variation), being in agreement with the previous
other calculations and with PIONEER/VOYAGER observations.

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The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph