Revisiting Spatial-Dependent Propagation Model with Latest Observations of Cosmic Ray Nuclei

TL;DR

This paper revisits the spatial-dependent cosmic ray propagation model to explain recent AMS-02 observations of light nuclei, successfully accounting for spectral anomalies and ratios with updated data.

Contribution

The study demonstrates that the spatial-dependent diffusion model can comprehensively explain recent cosmic ray spectral features and ratios observed by AMS-02.

Findings

Model reproduces the spectral upturns of secondary and primary cosmic rays.

Calculated cosmic ray ratios agree well with recent observations.

Spatial-dependent diffusion effectively explains spectral anomalies above 200 GV.

Abstract

Recently AMS-02 collaboration publish their measurements of light cosmic-ray nuclei, including lithium, beryllium, boron, carbon and oxygen. All of them reveal a prominent excess above $\sim$ 200 GV, coinciding with proton and helium. Particularly, the secondary cosmic rays even harden than the primary components above that break. One of the viable interpretations for above anomalies is the spatial-dependent diffusion process. Such model has been successfully applied to multiple observational phenomena, for example primary cosmic ray nuclei, diffuse gamma ray and anisotropy. In this work, we investigate the spatial-dependent propagation model in light of the new observational data. We find that such model is able to explain the upturn of secondary spectrum as well as the primary's. All the spectra can be well reproduced and the calculated ratios are also in good agreement with the observations.