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Related papers: Diffusive Versus Free-Streaming Cosmic Ray Transpo…

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Cosmic rays (CR) play an important role in dense molecular cores, affecting their thermal and dynamical evolution and initiating the chemistry. Several studies have shown that the formation of protostellar discs in collapsing clouds is…

Astrophysics of Galaxies · Physics 2015-06-17 Marco Padovani , Patrick Hennebelle , Daniele Galli

Diffuse interstellar clouds show large abundances of H_3^+ which can be maintained only by a high ionization rate of H_2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Nick Indriolo , Brian D. Fields , Benjamin J. McCall

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

We have obtained estimates for the cosmic-ray ionization rate (CRIR) in the Galactic disk, using a detailed model for the physics and chemistry of diffuse interstellar gas clouds to interpret previously-published measurements of the…

Astrophysics of Galaxies · Physics 2017-08-30 David A. Neufeld , Mark G. Wolfire

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 theory of cosmic-ray (CR) penetration into dense molecular clouds developed recently for relativistic particles by Chernyshov et al. (2024) is extended to non-relativistic CRs. Interstellar CRs streaming into the clouds are able to…

High Energy Astrophysical Phenomena · Physics 2025-10-06 D. O. Chernyshov , A. V. Ivlev , V. A. Dogiel

Galactic cosmic rays (CRs) play a crucial role in galaxy formation and evolution by altering gas dynamics and chemistry across multiple scales. Typical numerical simulations of CR transport assume a constant diffusion coefficient for the…

Astrophysics of Galaxies · Physics 2025-10-16 Sarah Thiele , Romain Teyssier

This paper studies cosmic ray (CR) transport in magneto hydrodynamic (MHD) turbulence. CR transport is strongly dependent on the properties of the magnetic turbulence. We perform test particle simulations to study the interactions of CR…

High Energy Astrophysical Phenomena · Physics 2022-02-23 Snehanshu Maiti , Kirit Makwana , Heshou Zhang , Huirong Yan

From the rate of hydrogen ionization and the gamma ray flux, we derived the spectrum of relativistic and subrelativistic cosmic rays (CRs) nearby and inside the molecular cloud Sgr B2 near the Galactic Center (GC). We studied two cases of…

High Energy Astrophysical Phenomena · Physics 2015-08-19 V. A. Dogiel , D. O. Chernyshov , A. M. Kiselev , M. Nobukawa , K. S. Cheng , C. Y. Hui , C. M. Ko , K. K. Nobukawa , T. G. Tsuru

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

In the standard Galactic cosmic-ray (CR) paradigm, protons are accelerated up to ~1 PeV by Galactic sources. While supernova remnants (SNRs) have been traditionally considered as the primary accelerators, recent observations by LHAASO and…

High Energy Astrophysical Phenomena · Physics 2026-01-22 Yutaka Fujita , Rohta Takahashi , Norita Kawanaka

Understanding cosmic ray (CR) diffusion in a partially ionized medium is both crucial and challenging. In this study, we investigate CR perpendicular superdiffusion and parallel transport in turbulent, partially ionized media using…

Astrophysics of Galaxies · Physics 2025-10-09 Yue Hu , Siyao Xu , Alex Lazarian , James M. Stone , Philip F. Hopkins

A proper modelling of the cosmic-ray ionisation rate within gas clouds is crucial to describe their chemical evolution accurately. However, this modelling is computationally demanding because it requires the propagation of cosmic rays…

Astrophysics of Galaxies · Physics 2025-07-08 G. Latrille , A. Lupi , S. Bovino , T. Grassi , G. Sabatini , M. Padovani

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

Cosmic rays (CRs) with ~GeV energies can contribute significantly to the energy and pressure budget in the interstellar, circumgalactic, and intergalactic medium (ISM, CGM, IGM). Recent cosmological simulations have begun to explore these…

Cosmic rays (CRs) at sub-TeV energies play a fundamental role in the chemical and dynamical evolution of molecular clouds, as they control the ionisation, dissociation, and excitation of H$_{2}$. Their characterisation is important both for…

One of the unsolved problems in cosmic ray (CR) physics is the small radial gradient of the gamma-ray intensity compared to the inferred CR source distribution in the Galactic disk. In diffusive CR propagation models the most natural…

Astrophysics · Physics 2007-05-23 D. Breitschwerdt , V. Dogiel , H. J. V"olk

Cosmic rays (CRs) are an integral part of the non-thermal pressure budget in the interstellar medium (ISM) and are the leading-order ionization mechanism in cold molecular clouds. We study the impacts that different microphysical CR…

We aim to elucidate cosmic ray (CR) propagation in the weakly ionized environments of supernova remnants (SNRs) basing our analysis on the cosmic ray cloud (CRC) model developed by \citet{2013ApJ...768...73M} and…

High Energy Astrophysical Phenomena · Physics 2020-01-15 L. Brahimi , A. Marcowith , V. S. Ptuskin

Starburst galaxies are efficient $\gamma$-ray producers, because their high supernova rates generate copious cosmic ray (CR) protons, and their high gas densities act as thick targets off which these protons can produce neutral pions and…

High Energy Astrophysical Phenomena · Physics 2020-02-26 Mark R. Krumholz , Roland M. Crocker , Siyao Xu , A. Lazarian , M. T. Rosevear , Jasper Bedwell-Wilson