Interpretation of the Spectra and Anisotropy of Galactic Cosmic Rays

Abstract

Recent measurements of the spectra and anisotropy of cosmic rays (CRs) show a fine structure that reflects the spectral hardenings of CRs nuclei at the rigidity R ∼ 200 GV followed by softenings at R ∼ 10 TV, and reveal complicated energy dependence of the amplitude and phase of anisotropy from 100 GeV to PeV. Numerous studies have shown that the existence of nearby CR sources and a local interstellar magnetic field (LIMF) near the solar system are crucial for such CR spectral and anisotropic patterns. In this work, we analyze the CR spectra of different CR components and the anisotropy considering the nearby Geminga supernova remnants (SNRs) source. In the calculation process, we also introduce the anisotropic diffusion of CRs induced by the LIMF based on the spatial-dependent propagation (SDP) model. As a result, our model can simultaneously account for the CR spectra and the anisotropy from 100 GeV to PeV. Future high-precision measurements of the CR anisotropy, for example, by the LHAASO experiment, would be of the essence in the assessment of our proposed model.

Keywords

• cosmic ray anisotropy
• cosmic ray spectra
• Geminga supernova remnants
• local interstellar magnetic field