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Related papers: On the Numerical Stability of the Diffusion Coeffi…

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The hypothesis is considered that the present Galactic cosmic ray spectrum is at present softer than its time average due to source intermittency. Measurements of muogenic nuclides underground could provide an independent measurement of the…

High Energy Astrophysical Phenomena · Physics 2015-06-15 David Eichler , Rahul Kumar , Martin Pohl

The estimation of light velocity dispertion caused by quantum fluctuations influence on electromagnetic wave propogation in four-dimensional space-time is presented. Analytical cosmological solutions for the flat and open Universe for the…

Astrophysics · Physics 2007-05-23 Yu. S. Grishkan , V. B. Petkov , E. G. Vertogradova

We report on measurements of self-diffusion coefficients in discrete numerical simulations of steady, homogeneous, collisional shearing flows of nearly identical, frictional, inelastic spheres. We focus on a range of relatively high solid…

Soft Condensed Matter · Physics 2021-04-01 Riccardo Artoni , Michele Larcher , James Jenkins , Patrick Richard

We have developed a new, very efficient numerical scheme to solve the CR diffusion convection equation that can be applied to the study of the nonlinear time evolution of CR modified shocks for arbitrary spatial diffusion properties. The…

Astrophysics · Physics 2009-11-11 T. W. Jones , H. Kang

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 circumgalactic medium (CGM) contains information on the cumulative effect of galactic outflows over time, generally thought to be caused by feedback from star formation and active galactic nuclei. Observations of such outflows via…

We describe and discuss the properties of three numerical methods for solving the diffusion equation for the transport of the chemical species and of the angular momentum in stellar interiors. We study through numerical experiments both…

Astrophysics · Physics 2009-11-10 Georges Meynet , Andre Maeder , Nami Mowlavi

We present the results on the source spectrum function for primary nuclei in galactic cosmic rays, where two distinct energy dependences are used for the source spectra. We discuss the evolution of the goodness of fit to B/C data with the…

Astrophysics · Physics 2007-05-23 Fiorenza Donato , David Maurin , Richard Taillet

Numerical simulations shed light onto earlier not trackable problem of magnetohydrodynamic (MHD) turbulence. They allowed to test the predictions of different models and choose the correct ones. Inevitably, this progress calls for revisions…

Astrophysics · Physics 2007-12-27 Huirong Yan , A. Lazarian

Numerical modeling of galactic cosmic rays (GCRs) penetration through the heliosphere to the vicinity of the Sun is considered. Galactic cosmic rays are charged particles with energies exceeding 10 MeV/nucl., originating from far beyond the…

High Energy Astrophysical Phenomena · Physics 2025-09-04 D. A. Shestakov , V. V. Izmodenov

The unprecedented quality of the data collected by the AMS-02 experiment onboard the International Space Station allowed us to address subtle questions concerning the origin and propagation of cosmic rays. Here we discuss the implications…

High Energy Astrophysical Phenomena · Physics 2019-06-05 Carmelo Evoli , Roberto Aloisio , Pasquale Blasi

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

We study the chaotic-like behavior of cosmological simulations by quantifying how minute perturbations grow over time and manifest as macroscopic differences in galaxy properties. When we run pairs of 'shadow' simulations that are identical…

Cosmic ray transport on galactic scales depends on the detailed properties of the magnetized, multiphase interstellar medium (ISM). In this work, we post-process a high-resolution TIGRESS magnetohydrodynamic simulation modeling a local…

High Energy Astrophysical Phenomena · Physics 2021-11-24 Lucia Armillotta , Eve C. Ostriker , Yan-Fei Jiang

In a previous study (Maurin et al., 2001), we explored the set of parameters describing diffusive propagation of cosmic rays (galactic convection, reacceleration, halo thickness, spectral index and normalization of the diffusion…

Astrophysics · Physics 2009-11-07 David Maurin , Richard Taillet , Fiorenza Donato

Context. The diffusive shock acceleration mechanism has been widely accepted as the acceleration mechanism for galactic cosmic rays. While self-consistent hybrid simulations have shown how power-law spectra are produced, detailed…

High Energy Astrophysical Phenomena · Physics 2015-06-04 M. Wolff , R. C. Tautz

In this work, we investigate a numerical procedure for recovering a space-dependent diffusion coefficient in a (sub)diffusion model from the given terminal data, and provide a rigorous numerical analysis of the procedure. By exploiting…

Numerical Analysis · Mathematics 2024-05-20 Bangti Jin , Xiliang Lu , Qimeng Quan , Zhi Zhou

Many stars, active galactic nuclei, accretion discs etc. are affected by the stochastic variations of temperature, turbulent gas motions, magnetic fields, number densities of atoms and dust grains. These stochastic variations influence on…

Solar and Stellar Astrophysics · Physics 2017-12-20 N. A. Silant'ev , G. A. Alekseeva , V. V. Novikov

Recent advances in both the MHD turbulence theory and cosmic ray observations call for revisions in the paradigm of cosmic ray transport. We use the models of magnetohydrodynamic turbulence that were tested in numerical simulation, in which…

High Energy Astrophysical Phenomena · Physics 2013-12-02 Huirong Yan , Siyao Xu

We consider anisotropic diffusion of Galactic cosmic rays in the Galactic magnetic field, using the Jansson-Farrar model for the field. In this paper we investigate the influence of source position on the cosmic ray flux at Earth in two…

Astrophysics of Galaxies · Physics 2020-01-29 A. AL-Zetoun , A. Achterberg