Anomalous Galactic Cosmic Rays in the Framework of AMS-02

TL;DR

This paper explains the observed spectral hardening of cosmic ray protons and helium nuclei at high energies by modeling a transition from normal diffusion to superdiffusion in cosmic ray propagation, aligning well with AMS-02 data.

Contribution

It introduces a diffusion-based model accounting for spectral features in cosmic rays, advancing understanding of cosmic ray acceleration and propagation mechanisms.

Findings

Proton and helium spectra match AMS-02 data well

Transition from normal diffusion to superdiffusion explains spectral hardening

Diffusion regime change affects particle acceleration efficiency

Abstract

The cosmic ray energy spectra of protons and helium nuclei, which are the most abundant components of cosmic radiation, exhibit a remarkable hardening at energies above one hundred GeV/nucleon. Recent data from AMS-02 confirms this feature with a higher significance. This data challenges the current models of cosmic ray acceleration in Galactic sources and propagation in the Galaxy. Here, we explain the observed break in the spectra of proton and helium nuclei in light of recent advances of cosmic ray diffusion theories in turbulent astrophysical sources as a result of a transition between different cosmic ray diffusion regimes. We reconstruct the observed cosmic ray spectra using the fact that transition from normal diffusion to superdiffusion changes the efficiency of particle acceleration and causes the change in the spectral index. We find that calculated proton and helium spectra match very well with the data.