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The coarse-grained propagation of Galactic cosmic rays (CRs) is traditionally constrained by phenomenological models of Milky Way CR propagation fit to a variety of direct and indirect observables; however, constraining the fine-grained…

Astrophysics of Galaxies · Physics 2024-02-07 Chad Bustard , John Wu

The way in which kinetic energy is distributed over the multiplicity of inertial (intermediate) scales is a fundamental feature of turbulence. According to Kolmogorov's 1941 theory, on the basis of a dimensional analysis, the form of the…

Fluid Dynamics · Physics 2011-10-21 Stefania Scarsoglio , Francesca De Santi , Daniela Tordella

We derive expressions for the time integrated spectrum of Cosmic Rays (CRs) that are accelerated in a decelerating relativistic shock wave and escape ahead of the shock. It is assumed that at any given time the CRs have a power law form,…

High Energy Astrophysical Phenomena · Physics 2011-01-27 Boaz Katz , Peter Meszaros , Eli Waxman

The propagation of high-energy cosmic rays through giant molecular clouds constitutes a fundamental process in astronomy and astrophysics. The diffusion of cosmic-rays through these magnetically turbulent environments is often studied…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Marco Fatuzzo , Fulvio Melia , Elizabeth Todd , Fred Adams

Cosmic-ray transport in astrophysical environments is often dominated by the diffusion of particles in a magnetic field composed of both a turbulent and a mean component. This process, which is two-fold turbulent mixing in that the particle…

High Energy Astrophysical Phenomena · Physics 2021-12-14 P. Reichherzer , L. Merten , J. Dörner , J. Becker Tjus , M. J. Pueschel , E. G. Zweibel

Precise measurements of the energy spectra of cosmic rays (CRs) show various kinds of features deviating from single power-laws, which give very interesting and important implications on their origin and propagation. Previous measurements…

Cosmic rays (CRs) are a dynamically important component of the interstellar medium (ISM) of galaxies. The $\sim$GeV CRs that carry most CR energy and pressure are likely confined by self-generated turbulence, leading them to stream along…

Astrophysics of Galaxies · Physics 2022-11-16 Matt L. Sampson , James R. Beattie , Mark R. Krumholz , Roland M. Crocker , Christoph Federrath , Amit Seta

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

The statistical properties of turbulence are considered to be universal at sufficiently small length scales, i. e., independent of boundary conditions and large-scale forces acting on the fluid. Analyzing data from numerical simulations of…

Astrophysics · Physics 2008-12-18 Wolfram Schmidt , Christoph Federrath , Ralf Klessen

We calculate spectra of escaping cosmic rays (CRs) accelerated at shocks produced by expanding Galactic superbubbles powered by multiple supernovae producing a continuous energy outflow in star-forming galaxies. We solve the generalized…

High Energy Astrophysical Phenomena · Physics 2020-01-28 Zhaowei Zhang , Kohta Murase , Peter Mészáros

Cosmic rays are a fundamental source of ionization for molecular and diffuse clouds, influencing their chemical, thermal, and dynamical evolution. The amount of cosmic rays inside a cloud also determines the $\gamma$-ray flux produced by…

High Energy Astrophysical Phenomena · Physics 2015-09-18 G. Morlino , S. Gabici , J. Krause

When a magnetised, thermal plasma containing a shock wave efficiently accelerates Cosmic Rays (CR) a reaction is exerted on the fluid structure. The simplest description of this process involves three conservation equations for the…

Astrophysics · Physics 2007-05-23 P. Duffy , L. O'C. Drury , H. J. Voelk

We present a theory of non-solar cosmic rays (CRs) in which the bulk of their observed flux is due to a single type of CR source at all energies. The total luminosity of the Galaxy, the broken power-law spectra with their observed slopes,…

High Energy Physics - Phenomenology · Physics 2009-09-29 Arnon Dar , Alvaro De Rujula

Recent advances on gamma-ray observations from SuperNova Remnants and Molecular Clouds offer the possibility to study in detail the properties of the propagation of escaping Cosmic Rays (CR). However, a complete theory for CR transport…

High Energy Astrophysical Phenomena · Physics 2015-09-09 Lara Nava , Stefano Gabici , Alexandre Marcowith , Giovanni Morlino , Vladimir Ptuskin

We use large-scale three-dimensional simulations of supersonic Euler turbulence to study the physics of a highly compressible cascade. Our numerical experiments describe non-magnetized driven turbulent flows with an isothermal equation of…

Astrophysics · Physics 2009-06-23 Alexei G. Kritsuk , Paolo Padoan , Rick Wagner , Michael L. Norman

The propagation of cosmic rays (CRs) in turbulent interstellar magnetic fields is typically described as a spatial diffusion process. This formalism predicts only a small deviation from an isotropic CR distribution in the form of a dipole…

High Energy Astrophysical Phenomena · Physics 2014-01-22 Markus Ahlers

Diffusion of cosmic rays (CRs) is the key process of understanding their propagation and acceleration. We employ the description of spatial separation of magnetic field lines in MHD turbulence in Lazarian & Vishniac (1999) to quantify the…

High Energy Astrophysical Phenomena · Physics 2016-12-21 A. Lazarian , Huirong Yan

In the Milky Way, cosmic rays (CRs) are dynamically important in the interstellar medium, contribute to hydrostatic balance, and may help regulate star formation. However, we know far less about the importance of CRs in galaxies whose gas…

Astrophysics of Galaxies · Physics 2021-01-27 Roland M. Crocker , Mark R. Krumholz , Todd A. Thompson

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

As the fundamental physical process with many astrophysical implications, the diffusion of cosmic rays (CRs) is determined by their interaction with magnetohydrodynamic (MHD) turbulence. We consider the magnetic mirroring effect arising…

High Energy Astrophysical Phenomena · Physics 2021-12-22 Alex Lazarian , Siyao Xu