Small-Scale Anisotropies of Cosmic Rays from Turbulent Flow

Yiran Zhang; Siming Liu

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arXiv · 2402.16554

Small-Scale Anisotropies of Cosmic Rays from Turbulent Flow

Yiran Zhang·Siming Liu

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Abstract

Within the classical convection--diffusion approximation, we show that the angular distribution of cosmic rays (CRs) in a highly turbulent flow may exhibit significant small-scale anisotropies. The CR intensity angular power spectrum $ C_\ell $ is then a direct reflection of interstellar turbulence, from which one expects $ C_\ell\propto\ell^{-\gamma -1} $ for $ \ell\gg 1 $, where $ \gamma $ is the power-law turbulence spectral index. Observations by IceCube and HAWC at TeV energies can be explained approximately with the Kolmogorov law $ \gamma =5/3 $ with a convection velocity dispersion of 20 km/s on the scale of 10 pc.

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Yiran Zhang, Siming Liu. 2024-02-26. Small-Scale Anisotropies of Cosmic Rays from Turbulent Flow. https://arxiv.org/abs/2402.16554

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