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Nonthermal particles can be produced due to incomplete thermalization at collisionless shocks and further accelerated to very high energies via diffusive shock acceleration. In a previous study we explored the cosmic ray (CR) acceleration…

Astrophysics · Physics 2017-01-18 Hyesung Kang

We use kinetic simulations of diffusive shock acceleration (DSA) to study the time-dependent evolution of plane, quasi-parallel, cosmic-ray (CR) modified shocks. Thermal leakage injection of low energy CRs and finite Alfv\'en wave…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Hyesung Kang , Dongsu Ryu , T. W. Jones

A numerical scheme that incorporates a thermal leakage injection model into a combined gas dynamics and cosmic ray (CR, hereafter) diffusion-convection code has been developed. The particle injection is followed numerically by filtering the…

Astrophysics · Physics 2009-11-07 Hyesung Kang , T. W. Jones , U. D. J. Gieseler

Using an improved version of the previously introduced CRASH (Cosmic Ray Acceleration SHock) code, we have calculated the time evolution of cosmic-ray (CR) modified quasi-parallel plane shocks for Bohm-like diffusion, including…

Astrophysics · Physics 2009-06-23 Hyesung Kang , T. W. Jones

Cosmological hydrodynamic simulations of large scale structure in the universe have shown that accretion shocks and merger shocks form due to flow motions associated with the gravitational collapse of nonlinear structures. Estimated speed…

Astrophysics · Physics 2015-06-24 Hyesung Kang , T. W. Jones

We reexamine nonlinear diffusive shock acceleration (DSA) at cosmological shocks in the large scale structure of the Universe, incorporating wave-particle interactions that are expected to operate in collisionless shocks. Adopting simple…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Hyesung Kang , Dongsu Ryu

We explore the physics of shock evolution and particle acceleration in non-relativistic collisionless shocks using multidimensional hybrid simulations. We analyze a wide range of physical parameters relevant to the acceleration of cosmic…

High Energy Astrophysical Phenomena · Physics 2015-05-28 L. Gargaté , A. Spitkovsky

One of the key questions to understanding the efficiency of diffusive shock acceleration of the cosmic rays (CRs) is the injection process from thermal particles. A self-consistent injection model based on the interactions of the…

Astrophysics · Physics 2007-05-23 U. D. J. Gieseler , T. W. Jones , Hyesung Kang

Using a new, second-order accurate numerical method we present dynamical simulations of oblique MHD cosmic ray (CR) modified plane shock evolution using the two-fluid model for diffusive particle acceleration. The numerical shocks evolve to…

Astrophysics · Physics 2009-10-22 Adam Frank , T. W. Jones , Dongsu Ryu

We examine diffusive shock acceleration (DSA) of the pre-exisiting as well as freshly injected populations of nonthermal, cosmic-ray (CR) particles at weak cosmological shocks. Assuming simple models for thermal leakage injection and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Hyesung Kang , Dongsu Ryu

We consider cosmic ray (CR) modified shocks with both streaming and diffusion in the two-fluid description. Previously, numerical codes were unable to incorporate streaming in this demanding regime, and have never been compared against…

High Energy Astrophysical Phenomena · Physics 2020-08-25 Tsun Hin Navin Tsung , S. Peng Oh , Yan-Fei Jiang

A well-known paradigm about the origin of Galactic cosmic rays (CRs) is that these high-energy particles are accelerated in the process of diffusive shock acceleration (DSA) at collisionless shocks (at least up to the so-called "knee"energy…

High Energy Astrophysical Phenomena · Physics 2023-04-12 Bojan Arbutina

We have developed a cosmic ray (CR) shock code in one dimensional spherical geometry with which the particle distribution, the gas flow and their nonlinear interaction can be followed numerically in a frame comoving with an expanding shock.…

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

We present new results characterizing cosmological shocks within adaptive mesh refinement N-Body/hydrodynamic simulations that are used to predict non-thermal components of large-scale structure. This represents the first study of shocks…

We calculate the energy spectra of cosmic ray (CR) protons and electrons at a plane shock with quasi-parallel magnetic fields, using time-dependent, diffusive shock acceleration (DSA) simulations, including energy losses via synchrotron…

High Energy Astrophysical Phenomena · Physics 2017-01-18 Hyesung Kang

Low sonic Mach number shocks form in the intracluster medium (ICM) during the formation of the large-scale structure of the universe. Nonthermal cosmic-ray (CR) protons are expected to be accelerated via diffusive shock acceleration (DSA)…

High Energy Astrophysical Phenomena · Physics 2019-10-02 Dongsu Ryu , Hyesung Kang , Ji-Hoon Ha

We discuss new methods to integrate the cosmic ray (CR) evolution equations coupled to magneto-hydrodynamics (MHD) on an unstructured moving mesh, as realised in the massively parallel AREPO code for cosmological simulations. We account for…

Astrophysics of Galaxies · Physics 2017-01-11 C. Pfrommer , R. Pakmor , K. Schaal , C. M. Simpson , V. Springel

Diffusive shock acceleration (DSA) of particles at collisionless shocks is the major accepted paradigm about the origin of cosmic rays (CRs). As a theory it was developed during the late 1970s in the so-called test-particle case. If one…

High Energy Astrophysical Phenomena · Physics 2023-10-03 Bojan Arbutina

Galactic cosmic rays (CRs) are accelerated at the forward shocks of supernova remnants (SNRs) via diffusive shock acceleration (DSA), an efficient acceleration mechanism that predicts power-law energy distributions of CRs. However,…

High Energy Astrophysical Phenomena · Physics 2021-11-24 Rebecca Diesing , Damiano Caprioli

During the formation of large-scale structures in the universe, weak internal shocks are induced within the hot ICM, while strong accretion shocks arise in the WHIM within filaments, and the warm-cold gas in voids surrounding galaxy…

High Energy Astrophysical Phenomena · Physics 2024-09-30 Hyesung Kang
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