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A correct description of cosmic-ray (CR) diffusion in turbulent plasma is essential for many astrophysical and heliospheric problems. This paper aims to present physical diffusion behavior of CRs in actual turbulent magnetic fields, model…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Siyao Xu , Huirong Yan

The spatial distribution of cosmic ray (CR) particles in the interstellar medium (ISM) is of major importance in radio astronomy, where its knowledge is essential for the interpretation of observations, and in theoretical astrophysics,…

Astrophysics of Galaxies · Physics 2023-06-28 Devika Tharakkal , Andrew P. Snodin , Graeme R. Sarson , Anvar Shukurov

A model is introduced, in which the irregularity spectrum of the Galactic magnetic field beyond the dissipation length scale is first a Kolmogorov spectrum $k^{-5/3}$ at small scales $\lambda \, = \, 2 \pi/k$ with $k$ the wave-number, then…

High Energy Astrophysical Phenomena · Physics 2015-11-16 P. L. Biermann , L. I. Caramete , A. Meli , B. N. Nath , E. -S. Seo , V. de Souza , J. Becker Tjus

We investigate the diffusion of cosmic rays (CR) close to their sources. Propagating individual CRs in purely isotropic turbulent magnetic fields with maximal scale of spatial variations Lmax, we find that CRs diffuse anisotropically at…

High Energy Astrophysical Phenomena · Physics 2012-06-29 G. Giacinti , M. Kachelriess , D. V. Semikoz

Cosmic rays (CRs) are ubiquitous in the interstellar medium (ISM) of nearby galaxies, but many of their properties are not well-constrained. Gamma-ray observations provide a powerful tool in this respect, allowing us to constrain both the…

High Energy Astrophysical Phenomena · Physics 2023-07-19 Maria Werhahn , Philipp Girichidis , Christoph Pfrommer , Joseph Whittingham

In our previous work, we have investigated Galactic cosmic ray (GCR) spectra and anisotropy from 100 GeV to PeV, under anisotropic propagation model with axisymmetric distributed galactic sources. Numerous observational evidence have…

High Energy Astrophysical Phenomena · Physics 2024-12-24 Aifeng Li , Zhaodong Lv , Wei Liu , Yiqing Guo , Fangheng Zhang

We introduce a static toy model of the cosmic ray (CR) universe in which cosmic ray propagation is taken to be diffusive and cosmic ray sources are distributed randomly with a density the same as that of local L* galaxies, $5 \times…

Astrophysics · Physics 2007-10-29 Roger Clay , Roland M. Crocker

Under nonuniform convection, the distribution of diffusive particles can exhibit dipole and quadrupole anisotropy induced by the fluid inertial and shear force, respectively. These convection-related anisotropies, unlike the Compton-Getting…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Yiran Zhang , Siming Liu , Dejin Wu

Determining the spatial distribution of Galactic cosmic rays (CRs) is fundamental to understand how these particles propagate in interstellar space and to infer their source spectra. The most sensitive method of studying this problem is…

High Energy Astrophysical Phenomena · Physics 2025-09-26 Paolo Lipari , Silvia Vernetto

Propagation of cosmic rays (CRs) in turbulent and magnetized astrophysical media is a long-standing problem that requires both understanding of the properties of turbulent magnetic fields and their interaction with energetic particles. This…

Astrophysics of Galaxies · Physics 2023-04-07 Alex Lazarian , Siyao Xu , Yue Hu

We revisit propagation of galactic cosmic rays (CRs) in light of recent advances in CR diffusion theory in realistic interstellar turbulence. We use a tested model of turbulence in which it has been shown that fast modes dominate scattering…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Carmelo Evoli , Huirong Yan

Cosmic rays (CR) propagate through the galactic scales down to the smaller scales at which stars form. CRs are close to energy equipartition with the other components of the interstellar medium and can provide a support against gravity if…

Astrophysics of Galaxies · Physics 2019-02-13 Benoît Commerçon , Alexandre Marcowith , Yohan Dubois

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…

High Energy Astrophysical Phenomena · Physics 2014-12-01 G. Giacinti

We have developed a model which aims to reproduce observational data of many kinds related to cosmic-ray (CR) origin and propagation: direct measurements of nuclei, antiprotons, electrons and positrons, gamma-rays, and synchrotron…

Astrophysics · Physics 2009-10-31 I. V. Moskalenko , A. W. Strong

We argue that the diffusion of cosmic rays in the Galactic magnetic field has to be strongly anisotropic. As a result, the number of CR sources contributing to the local CR flux is reduced by a factor $\sim 200$. The CR density is therefore…

High Energy Astrophysical Phenomena · Physics 2019-05-22 M. Kachelriess

Recently, Zhang & Liu (2024) proposed a turbulent convection model for multiscale anisotropies of cosmic rays (CRs), with an assumption of isotropic diffusion such that the anisotropies are statistically isotropic. However, this assumption…

High Energy Astrophysical Phenomena · Physics 2025-06-26 Yiran Zhang , Siming Liu

We investigate the possibility that the cosmic ray (CR) knee is entirely explained by the energy-dependent CR leakage from the Milky Way. We test this hypothesis calculating the trajectories of individual CRs with energies between…

High Energy Astrophysical Phenomena · Physics 2014-08-22 G. Giacinti , M. Kachelriess , D. V. Semikoz

Galactic transport models for cosmic rays involve the diffusive motion of these particles in the interstellar medium. Due to the large-scale structured galactic magnetic field this diffusion is anisotropic with respect to the local field…

High Energy Astrophysical Phenomena · Physics 2013-06-07 Frederic Effenberger , Horst Fichtner , Klaus Scherer , Ingo Büsching

Cosmic ray propagation in the Galaxy is shortly reviewed. In particular we consider the self-consistent models of CR propagation. In these models CR streaming instability driven by CR anisotropy results in the Alfv\'enic turbulence which in…

High Energy Astrophysical Phenomena · Physics 2015-06-23 V. N. Zirakashvili

Models for cosmic ray (CR) dynamics fundamentally depend on the rate of CR scattering from magnetic fluctuations. In the ISM, for CRs with energies ~MeV-TeV, these fluctuations are usually attributed either to 'extrinsic turbulence' (ET) -…

High Energy Astrophysical Phenomena · Physics 2022-11-10 Philip F. Hopkins , Jonathan Squire , Iryna S. Butsky , Suoqing Ji