Small-scale Anisotropies of Cosmic Rays from Turbulent Flow

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 ℓ is then a direct reflection of interstellar turbulence, from wh...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2024-03, Vol.964 (1), p.L1
Main Authors: Zhang, Yiran, Liu, Siming
Format: Article
Language:English
Subjects:
Angular distribution
Convection
Cosmic ray astronomy
Cosmic ray showers
Cosmic rays
Fluid dynamics
Galactic cosmic rays
High energy astrophysics
Interstellar dynamics
Interstellar medium
Interstellar plasma
Interstellar turbulence
Particle astrophysics
Turbulence
Turbulent flow
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Summary: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 ℓ is then a direct reflection of interstellar turbulence, from which one expects C ℓ ∝ ℓ − γ −1 for ℓ ≫ 1, where γ is the power-law turbulence spectral index. Observations by IceCube and HAWC at TeV energies can be explained approximately with the Kolmogorov law γ = 5/3 with a convection velocity dispersion of 20 km s −1 on the scale of 10 pc.
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/ad2df4