A study on the sharp knee and fine structures of cosmic ray spectra

TL;DR

This paper models cosmic ray spectra features around the knee region using nuclei-photon interactions near young supernova remnants, explaining multiple observed spectral irregularities and particle excesses with a unified source scenario.

Contribution

It introduces a model that explains the sharp knee, spectral structures, and particle excesses in cosmic rays using a single set of source parameters related to young supernova remnants.

Findings

The model explains the knee and its sharpness.

It accounts for spectral irregular structures.

It reproduces electron/positron excesses.

Abstract

The paper investigates the overall and detailed features of cosmic ray (CR) spectra in the knee region using the scenario of nuclei-photon interactions around the acceleration sources. Young supernova remnants can be the physical realities of such kind of CR acceleration sites. The results show that the model can well explain the following problems simultaneously with one set of source parameters: the knee of CR spectra and the sharpness of the knee, the detailed irregular structures of CR spectra, the so-called "component B" of Galactic CRs, and the electron/positron excesses reported by recent observations. The coherent explanation serves as evidence that at least a portion of CRs might be accelerated at the sources similar to young supernova remnants, and one set of source parameters indicates that this portion mainly comes from standard sources or from a single source.