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Related papers: Spectrally resolved cosmic ray hydrodynamics -- I.…

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Diffusion of particles in velocity space undergoing turbulent field was extensively studied in the problem of warm beam relaxation. Under low field intensities the diffusion is described by the Fokker-Planck equation with the diffusion…

Plasma Physics · Physics 2007-05-23 Anatoly Zagorodny , Volodymyr Zasenko , Jan Weiland

It is well known that cosmic rays (CRs) contribute significantly to the pressure of the interstellar medium in our own Galaxy, suggesting that they may play an important role in regulating star formation during the formation and evolution…

Astrophysics · Physics 2009-11-11 Martin Jubelgas , Volker Springel , Torsten A. Ensslin , Christoph Pfrommer

We developed a new model for the production and propagation of spectrally resolved primary and secondary Cosmic Ray (CR) nuclei elements within the framework of the Cosmic Ray Energy Spectrum (CRESP) module of the PIERNIK MHD code. We…

Cosmic rays (CRs) play a decisive role within our own Galaxy. They provide partial pressure support against gravity, they trace past energetic events such as supernovae, and they reveal the underlying structure of the baryonic matter…

Astrophysics · Physics 2009-11-11 Torsten A. Ensslin , Christoph Pfrommer , Volker Springel , Martin Jubelgas

A spectral solution method is proposed to solve a previuously developed non-equilibrium statistical model describing partial thermalization of produced charged hadrons in relativistic heavy-ion collisions, thus improving the accuracy of the…

High Energy Physics - Phenomenology · Physics 2024-10-10 A. Rizzi , G. Wolschin

We introduce CRK-HACC, an extension of the Hardware/Hybrid Accelerated Cosmology Code (HACC), to resolve gas hydrodynamics in large-scale structure formation simulations of the universe. The new framework couples the HACC gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-01 Nicholas Frontiere , J. D. Emberson , Michael Buehlmann , Joseph Adamo , Salman Habib , Katrin Heitmann , Claude-André Faucher-Giguère

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 present a set of new numerical methods that are relevant to calculating radiation pressure terms in hydrodynamics calculations, with a particular focus on massive star formation. The radiation force is determined from a Monte Carlo…

Solar and Stellar Astrophysics · Physics 2015-06-23 Tim J. Harries

We derive a consistent set of moments equations for CR-magnetohydrodynamics, assuming a gyrotropic distribution function (DF). Unlike previous efforts we derive a closure, akin to the M1 closure in radiation hydrodynamics (RHD), that is…

High Energy Astrophysical Phenomena · Physics 2022-03-18 Philip F. Hopkins , Jonathan Squire , Iryna S. Butsky

Recently, the fractional Fokker-Planck equations (FFPEs) with multiple internal states are built for the particles undergoing anomalous diffusion with different waiting time distributions for different internal states, which describe the…

Numerical Analysis · Mathematics 2020-05-06 Daxin Nie , Jing Sun , Weihua Deng

We present a new code that significantly extends CRPropa's capabilities to model the ensemble averaged transport of charged cosmic rays in arbitrary turbulent magnetic fields. The software is based on solving a set of stochastic…

High Energy Astrophysical Phenomena · Physics 2024-10-03 Lukas Merten , Sophie Aerdker

Fractional Fokker-Planck equation plays an important role in describing anomalous dynamics. To the best of our knowledge, the existing discussions mainly focus on this kind of equation involving one diffusion operator. In this paper, we…

Numerical Analysis · Mathematics 2021-09-08 Jing Sun , Weihua Deng , Daxin Nie

The Fokker-Planck equation is a partial differential equation that describes the evolution of a probability distribution over time. It is used to model a wide range of physical and biological phenomena, such as diffusion, chemical…

Computational Physics · Physics 2023-11-29 Wisit Mangthas , Waipot Ngamsaad

The quasilinear theory for cosmic ray propagation is a well known and widely accepted theory. In this paper, we discuss the different contributions to the pitch-angle Fokker-Planck coefficient from large and small scales for slab geometry…

Astrophysics · Physics 2011-05-12 A. Shalchi , H. Yan , A. Lazarian

Current-day cosmic ray (CR) propagation studies use static Milky-Way models and fit parametrized source distributions to data. Instead, we use three-dimensional magneto-hydrodynamical (MHD) simulations of isolated galaxies with the…

High Energy Astrophysical Phenomena · Physics 2021-05-25 Maria Werhahn , Christoph Pfrommer , Philipp Girichidis , Ewald Puchwein , Rüdiger Pakmor

We investigate the transport of spectrally resolved cosmic ray (CR) protons with kinetic energies between $1-100$ GeV within the dynamic, multiphase interstellar medium (ISM), using a two-moment CR fluid solver applied to a TIGRESS MHD…

High Energy Astrophysical Phenomena · Physics 2025-07-02 Lucia Armillotta , Eve C. Ostriker , Nora B. Linzer

Chain of kinetic equations for non-equilibrium single, double and s-particle distribution functions of particles is obtained taking into account nonlin- ear hydrodynamic fluctuations. Non-equilibrium distribution function of non-linear…

Statistical Mechanics · Physics 2015-10-28 Petro Hlushak , Mykhailo Tokarchuk

Cosmic ray (CR) hydrodynamics is a (re-)emerging field of high interest due to the importance of CRs for the dynamical evolution of the interstellar, the circumgalactic, and the intracluster medium. In these environments, CRs with GeV…

High Energy Astrophysical Phenomena · Physics 2021-11-03 Timon Thomas , Christoph Pfrommer

A numerical method for integrating the equations describing a dynamically coupled system made of a fluid and cosmic-rays is developed. In smooth flows the effect of CR pressure is accounted for by modification of the characteristic…

Astrophysics · Physics 2008-11-26 Francesco Miniati

The reformulation of nonequilibirum thermodynamics, to include the treatment of thermodynamic fluctuations, is applied to the hydrodynamic fluctuations of a simple fluid. It is shown that the nonequilibrium thermodynamic scheme leads to the…

Statistical Mechanics · Physics 2007-05-23 J. M. Rubi , P. Mazur