SMALL-SCALE ANISOTROPIES OF COSMIC RAYS FROM RELATIVE DIFFUSION

Journal Article · Thu Dec 10 00:00:00 EST 2015 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/815/1/L2· OSTI ID:22518665

Ahlers, Markus ^[1]; Mertsch, Philipp ^[2]

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1. WIPAC and Department of Physics, University of Wisconsin–Madison, Madison, WI 53706 (United States)
2. Kavli Institute for Particle Astrophysics and Cosmology, Menlo Park, CA 94025 (United States)

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.

• OSTI ID: 22518665
• Journal Information: Astrophysical Journal Letters, Vol. 815, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ANISOTROPY
COSMIC RADIATION
DIFFUSION
DIFFUSION EQUATIONS
DIPOLES
ENERGY SPECTRA
MAGNETIC FIELDS
SCATTERING
TEV RANGE
TURBULENCE