Cosmic ray propagation in the interstellar magnetic fields

Abstract

The propagation of TeV-PeV cosmic rays (CR) in our Galaxy can be described as a diffusive process. We discuss here two effects, with important observational consequences, that cannot be predicted by the diffusion approximation in its usual form. First, we present an explanation for the CR anisotropies observed at small angular scales on the sky. We show that the local magnetic field configuration within a CR mean free path from Earth naturally results in CR flux anisotropies at small and medium scales. Second, we point out that TeV-PeV CRs should be expected to diffuse strongly anisotropically in the interstellar medium on scales smaller than the maximum scale of spatial fluctuations of the field, $\sim 100$ pc. This notably questions the usual assumptions on CR diffusion around sources.

arXiv comment9 pages, 4 figures. Published in Plasma Physics and Controlled Fusion. Invited paper for the 40th EPS conference on plasma physics (2013)

References in corpus (29)

• Cosmic-ray propagation and interactions in the Galaxy
• Propagation of cosmic-ray nucleons in the Galaxy
• PAMELA Measurements of Cosmic-ray Proton and Helium Spectra
• Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight
• Cosmic-Ray Nuclei, Antiprotons and Gamma-rays in the Galaxy: a New Diffusion Model
• Cosmic ray acceleration and escape from supernova remnants
• Transport of Cosmic Rays in Chaotic Magnetic Fields
• Spectral breaks as a signature of cosmic ray induced turbulence in the Galaxy
• Anisotropy and Corotation of Galactic Cosmic Rays
• Discovery of Localized Regions of Excess 10-TeV Cosmic Rays
• Observation of the Anisotropy of 10 TeV Primary Cosmic Ray Nuclei Flux with the Super-Kamiokande-I Detector
• The Large Scale Cosmic-Ray Anisotropy as Observed with Milagro
• Observation of an Anisotropy in the Galactic Cosmic Ray arrival direction at 400 TeV with IceCube
• Observation of Cosmic Ray Anisotropy with the IceTop Air Shower Array
• Unified interpretation of cosmic-ray nuclei and antiproton recent measurements
• The Anisotropy of Galactic Cosmic Rays as a Product of Stochastic Supernova Explosions
• Local Magnetic Turbulence and TeV-PeV Cosmic Ray Anisotropies
• The spatial energy spectrum of magnetic fields in our Galaxy
• Magnetic reconnection as the cause of cosmic ray excess from the heliospheric tail
• Propagation of galactic cosmic rays in the presence of self-generated turbulence
• Anisotropy of TeV Cosmic Rays and the Outer Heliospheric Boundaries
• The Interstellar Magnetic Field Close to the Sun II
• The puzzling MILAGRO hot spots
• Probing Nearby CR Accelerators and ISM Turbulence with Milagro Hot Spots
• Filamentary Diffusion of Cosmic Rays on Small Scales
• Anisotropic Cosmic Ray Diffusion and its Implications for Gamma-Ray Astronomy
• Comparisons of the Interstellar Magnetic Field Directions obtained from the IBEX Ribbon and Interstellar Polarizations
• The problem of small angular scale structure in the cosmic ray anisotropy data
• How Local is the Local Interstellar Magnetic Field?