The role of the Galactic Halo and the Single Source in the formation of the cosmic ray anisotropy

TL;DR

This paper explores how the Galactic Halo and a potential Single Source influence cosmic ray anisotropy, suggesting the Halo's size and distribution dilute anisotropy and that a Single Source may cause minor deviations at high energies.

Contribution

It presents a model explaining cosmic ray anisotropy by the combined effects of the Halo and a Single Source, highlighting the Halo's role in isotropy.

Findings

Halo's large size helps explain isotropy and low spectral structure.

Dilution of anisotropy by Halo cosmic rays accounts for small dipole amplitude.

Minor deviations suggest contribution from a Single Source with opposite phase.

Abstract

The existence of the cosmic ray Halo in our Galaxy has been discussed for more than half a century. If it is real it could help to explain some puzzling features of the cosmic ray flux: its small radial gradient, nearly perfect isotropy and the low level of the fine structure in the energy spectra of the various particles. All these features could be understood if: (a) the Halo has a big size (b) cosmic rays in the Halo have a unform spatial distribution and (c) the cosmic ray density in the Halo is comparable or even higher than that in the Galactic Disk. The main topic of the paper concerns the present status of the anisotropy and a model for its formation. In our model the extremely small amplitude of the dipole anisotropy is due to the dilution of the anisotropy in the Disk by the dominating isotropic cosmic rays from the Halo. Some minor deviations from complete isotropy in the sub-PeV and PeV energy regions point out to the possible contribution of the Single Source with the phase of its first harmonic opposite to the phase produced by the Disk.