Non-linear acceleration at supernova remnant shocks and the hardening in the cosmic ray spectrum

Abstract

In the last few years several experiments have shown that the cosmic ray spectrum below the knee is not a perfect power-law. In particular, the proton and helium spectra show a spectral hardening by ~ 0.1-0.2 in spectral index at particle energies of ~ 200-300 GeV/nucleon. Moreover, the helium spectrum is found to be harder than that of protons by ~ 0.1 and some evidence for a similar hardening was also found in the spectra of heavier elements. Here we consider the possibility that the hardening may be the result of a dispersion in the slope of the spectrum of cosmic rays accelerated at supernova remnant shocks. Such a dispersion is indeed expected within the framework of non-linear theories of diffusive shock acceleration, which predict steeper (harder) particle spectra for larger (smaller) cosmic ray acceleration efficiencies.

References in corpus (7)

• Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight
• Observations of the young supernova remnant RX J1713.7-3946 with the Fermi Large Area Telescope
• Origin of the Cosmic Ray Spectral Hardening
• Simulations and Theory of Ion Injection at Non-relativistic Collisionless Shocks
• Indications for a high-rigidity break in the cosmic-ray diffusion coefficient
• The influence of the Alfvénic drift on the shape of cosmic ray spectra in SNRs
• Elemental energy spectra of cosmic rays measured by CREAM-II

Cited by in corpus (6)

• Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova Remnants
• Cosmic ray driven galactic winds
• On the origin of the spectral features observed in the cosmic ray spectrum
• Transport parameters from AMS-02 F/Si data and fluorine source abundance
• On the stochastic nature of Galactic cosmic-ray sources
• Deciphering the Electron Spectral Hardening in AMS-02