Small-Scale Anisotropies of Cosmic Rays from Relative Diffusion

Abstract

The arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It has been argued that this small-scale structure can naturally arise from cosmic ray scattering in local turbulent magnetic fields that distort a global dipole anisotropy set by diffusion. We study this effect in terms of the power spectrum of cosmic ray arrival directions and show that the strength of small-scale anisotropies is related to properties of relative diffusion. We provide a formalism for how these power spectra can be inferred from simulations and motivate a simple analytic extension of the ensemble-averaged diffusion equation that can account for the effect.

5 pages, 2 figures, version to appear in ApJL

References in corpus (9)

• Anisotropy and Corotation of Galactic Cosmic Rays
• Discovery of Localized Regions of Excess 10-TeV Cosmic Rays
• The Large Scale Cosmic-Ray Anisotropy as Observed with Milagro
• Evolution of the cosmic ray anisotropy above 10^{14} eV
• A common solution to the cosmic ray anisotropy and gradient problems
• Observation of Small-scale Anisotropy in the Arrival Direction Distribution of TeV Cosmic Rays with HAWC
• Solution to the cosmic ray anisotropy problem
• Small-Scale Anisotropies of Cosmic Rays from Relative Diffusion
• Angular Power Spectra with Finite Counts

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• Observation of Anisotropy of TeV Cosmic Rays with Two Years of HAWC
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• Large-Scale Cosmic-Ray Anisotropy as a Probe of Interstellar Turbulence
• TeV Cosmic-Ray Anisotropy from the Magnetic Field at the Heliospheric Boundary
• A New Maximum-Likelihood Technique for Reconstructing Cosmic-Ray Anisotropy at All Angular Scales
• Explaining TeV Cosmic-Ray Anisotropies with Non-Diffusive Cosmic-Ray Propagation
• Measurements and implications of cosmic ray anisotropies from TeV to trans-EeV energies
• No longer ballistic, not yet diffusive--the formation of cosmic ray small-scale anisotropies
• Observation of Cosmic-Ray Anisotropy in the Southern Hemisphere with 12 yr of Data Collected by the IceCube Neutrino Observatory
• Cosmic Ray Small-Scale Anisotropies in Quasi-Linear Theory
• Large- and Medium-Scale Anisotropies in the Arrival Directions of Cosmic Rays observed with KASCADE-Grande
• Comic ray flux anisotropies caused by astrospheres
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• Diffusion of relativistic charged particles and field lines in isotropic turbulence: I. Numerical simulations
• Cosmic Ray transport in mixed magnetic fields and their role on the observed anisotropies
• TeV-PeV Cosmic-Ray Anisotropy and Local Interstellar Turbulence
• Chaotic Behavior of Trapped Cosmic Rays
• The Dipole Anisotropy of Galactic Cosmic Rays