Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reconciling cosmic ray diffusion with Galactic magnetic field models   We calculate the diffusion coefficients of charged cosmic rays (CR)
propagating in regular and turbulent magnetic fields. If the magnetic field is
dominated by an isotropic turbulent component, we find that CRs reside too long
in the Galactic disc. As a result, CRs overproduce secondary nuclei like boron
for any reasonable values of the strength and the coherence length of an
isotropic turbulent field. We conclude therefore that the propagation of
Galactic CRs has to be strongly anisotropic because of a sufficiently strong
regular field and/or of an anisotropy in the turbulent field. As a consequence,
the number of sources contributing to the local CR flux is reduced by a factor
${\cal O}(100)$ compared to the case of isotropic CR diffusion.

26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
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The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex