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Cosmic ray (CR) electrons reveal key insights into the non-thermal physics of the interstellar medium, galaxies, galaxy clusters, and active galactic nuclei by means of their inverse Compton {\gamma}-ray emission and synchrotron emission in…

High Energy Astrophysical Phenomena · Physics 2019-09-24 Georg Winner , Christoph Pfrommer , Philipp Girichidis , Rüdiger Pakmor

Efficient acceleration of cosmic rays (via the mechanism of diffusive shock acceleration) requires turbulent, amplified magnetic fields in the shock's upstream region. We present results of multidimensional particle-in-cell simulations…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Thomas Stroman , Martin Pohl , Jacek Niemiec

The injection rate of suprathermal protons into the diffusive shock acceleration process should vary strongly over the surface of supernova remnant shocks. These variations and the absolute value of the injection rate are investigated. In…

Astrophysics · Physics 2007-05-23 H. J. Voelk , E. G. Berezhko , L. T. Ksenofontov

Diffusive shock acceleration is the prime candidate for efficient acceleration of cosmic rays. Galactic cosmic rays are believed to originate predominantly from this process in supernova remnant shock waves. Confinement of the cosmic rays…

High Energy Astrophysical Phenomena · Physics 2011-10-07 K. M. Schure , A. R. Bell

We analyze the properties of Large Scale Shocks in a cosmological volume of size 103Mpc/h simulated with the public 1.0.1 release of the ENZO code. Different methods to identify and characterize shocks in post processing are discussed…

Astrophysics · Physics 2009-11-13 F. Vazza , G. Brunetti , C. Gheller

Theoretical studies of cosmic ray particle acceleration in the first-order Fermi process at relativistic shocks are reviewed. At the beginning we discuss the acceleration processes acting at mildly relativistic shock waves. An essential…

Astrophysics · Physics 2007-05-23 Michal Ostrowski

Context. Observation of Balmer lines from the region around the forward shock of supernova remnants (SNR) may provide valuable information on the shock dynamics and the efficiency of particle acceleration at the shock. Aims. We calculated…

High Energy Astrophysical Phenomena · Physics 2015-06-17 G. Morlino , P. Blasi , R. Bandiera , E. Amato

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

The properties of the Galactic supernova remnant SN 1006 are theoretically reanalysed. Nonlinear kinetic theory is used to determine the acceleration efficiency of cosmic rays (CRs) in the supernova remnant SN 1006. The known range of…

High Energy Astrophysical Phenomena · Physics 2011-03-22 E. G. Berezhko , L. T. Ksenofontov , H. J. Voelk

We simulate time-dependent particle acceleration in the blast wave of a young supernova remnant (SNR), using a Monte Carlo approach for the diffusion and acceleration of the particles, coupled to an MHD code. We calculate the distribution…

High Energy Astrophysical Phenomena · Physics 2015-05-18 K. M. Schure , A. Achterberg , R. Keppens , Jacco Vink

Shocks waves are a ubiquitous feature of many astrophysical plasma systems, and an important process for energy dissipation and transfer. The physics of these shock waves are frequently treated/modeled as a collisional, fluid MHD…

Plasma Physics · Physics 2021-11-17 Colby C. Haggerty , Antoine Bret , Damiano Caprioli

We use large hybrid (kinetic protons-fluid electrons) simulations to investigate the transport of energetic particles in self-consistent electromagnetic configurations of collisionless shocks. In previous papers of this series, we showed…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Damiano Caprioli , Anatoly Spitkovsky

The problem of accelerating cosmic rays is one of fundamental importance, particularly given the uncertainty in the conditions inside the acceleration sites. Here we examine Diffusive Shock Acceleration in arbitrary turbulent magnetic…

High Energy Astrophysical Phenomena · Physics 2019-03-06 John Daniel Riordan , Asaf Pe'er

We use fully kinetic particle-in-cell simulations with unprecedentedly large transverse box sizes to study particle acceleration in weakly-magnetized mildly relativistic shocks traveling at a velocity $\approx 0.75c$ and a Mach number of…

High Energy Astrophysical Phenomena · Physics 2019-04-10 Patrick Crumley , Damiano Caprioli , Sera Markoff , Anatoly Spitkovsky

Collisionless shocks are often studied in two spatial dimensions (2D), to gain insights into the 3D case. We analyze diffusive shock acceleration for an arbitrary number $N\in\mathbb{N}$ of dimensions. For a non-relativistic shock of…

High Energy Astrophysical Phenomena · Physics 2020-07-07 Assaf Lavi , Ofir Arad , Yotam Nagar , Uri Keshet

Merging galaxy clusters exhibit strong observational evidence for efficient particle acceleration in the intracluster medium (ICM), particularly in the form of synchrotron-emitting radio relics and halos. Cosmic ray (CR) electrons are…

High Energy Astrophysical Phenomena · Physics 2025-10-29 Rebecca Diesing , Ludwig Böss , Damiano Caprioli

Precise measurements of galactic cosmic rays revealed a significant difference between the rigidity spectral indices of protons and helium ions. This finding is a notable contrast to the commonly accepted theoretical prediction that…

High Energy Astrophysical Phenomena · Physics 2019-02-27 A. Hanusch , T. Liseykina , M. Malkov

According to structure formation simulations, weak shocks with typical Mach number, $M_{\rm s}\lesssim 3$, are expected to form in merging galaxy clusters. The presence of such shocks has been indicated by X-ray and radio observations of…

High Energy Astrophysical Phenomena · Physics 2017-07-26 Hyesung Kang , Dongsu Ryu , T. W. Jones

This study explores the dynamical impact of cosmic rays (CRs) in Milky Way-like galaxies using the Rhea simulation suite. Cosmic rays, with their substantial energy density, influence the interstellar medium (ISM) by supporting galactic…

A new numerical model of the nonlinear diffusive shock acceleration is presented. It is used for modeling of particle acceleration in supernova remnants. The model contains coupled spherically symmetric hydrodynamic equations and the…

High Energy Astrophysical Phenomena · Physics 2015-05-30 V. N. Zirakashvili , V. S. Ptuskin