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Diffusive shock acceleration (DSA), as an acceleration process for Galactic electrons at the solar wind termination shock (TS), is investigated with a comprehensive numerical model which incorporates shock-acceleration, particle drifts and…

Space Physics · Physics 2017-11-30 M. S. Potgieter , P. L. Prinsloo , R. D. Strauss

We explore the shock acceleration model for giant radio relics, in which relativistic electrons are accelerated via diffusive shock acceleration (DSA) by merger-driven shocks in the outskirts of galaxy clusters. In addition to DSA,…

High Energy Astrophysical Phenomena · Physics 2017-09-06 Hyesung Kang

The mechanism of diffusive Fermi acceleration at collisionless plasma shock waves is widely invoked in astrophysics to explain the appearance of non-thermal particle populations in a variety of environments, including sites of cosmic ray…

Astrophysics · Physics 2007-05-23 Matthew G. Baring

We perform Monte Carlo simulations of diffusive shock acceleration at highly relativistic oblique shock waves. High upstream flow Lorentz gamma factors are used, which are relevant to models of ultra relativistic particle shock acceleration…

Astrophysics · Physics 2010-11-15 A. Meli , J. J. Quenby

Shocks of supernova remnants (SNRs) accelerate charged particles up to 100 TeV range via diffusive shock acceleration (DSA) mechanism. It is believed that shocks of SNRs are the main contributors to the pool of Galactic cosmic rays,…

High Energy Astrophysical Phenomena · Physics 2023-04-05 Jacco Vink , Aya Bamba

Motivated by cosmic ray (CR) re-acceleration at a potential Galactic Wind Termination Shock (GWTS), we present a numerical model for time-dependent Diffusive Shock Acceleration (DSA). We use the stochastic differential equation solver…

High Energy Astrophysical Phenomena · Physics 2023-12-07 Sophie Aerdker , Lukas Merten , Julia Becker Tjus , Dominik Walter , Frederic Effenberger , Horst Fichtner

Theoretical concepts ofn cosmic ray particle acceleration at relativistic plasma flows -- shocks and shear layers -- are reviewed. We begin with a discussion of mildly relativistic shock waves. The role of oblique field configurations and…

Astrophysics · Physics 2007-05-23 M. Ostrowski

Estimating the cosmic-ray acceleration efficiency $ \epsilon $ in supernova remnants (SNRs) through observations is a challenging task in general. Based on the Rankine-Hugoniot shock conditions, we find an anticorrelation between $ \epsilon…

High Energy Astrophysical Phenomena · Physics 2018-12-21 Yiran Zhang , Siming Liu

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

The outflows from gamma ray bursts, active galactic nuclei and relativistic jets in general interact with the surrounding media through collisionless shocks. With three dimensional relativistic particle-in-cell simulations we investigate…

Astrophysics · Physics 2010-11-11 C. B. Hededal , T. Haugboelle , J. T. Frederiksen , Å. Nordlund

Supernova remnants (SNRs) are believed to produce the majority of galactic cosmic rays (CRs). SNRs harbor non-relativistic collisionless shocks responsible for acceleration of CRs via diffusive shock acceleration (DSA), in which particles…

High Energy Astrophysical Phenomena · Physics 2022-12-20 Artem Bohdan

Diffusive shock acceleration in the environs of a remnant's expanding shell is a popular candidate for the origin of SNR gamma-rays. In this paper, results from our study of non-linear effects in shock acceleration theory and their impact…

The theory of particle acceleration at shock fronts is briefly reviewed, with special emphasis on the production of the particles responsible for the nonthermal emission from blazars. The flat radio/IR spectra of these sources cannot be…

Astrophysics · Physics 2007-05-23 J. G. Kirk

This review presents the fundamentals of the particle acceleration processes active in interstellar medium (ISM), which are essentially based on the so-called Fermi mechanism theory. More specifically, the review presents here in more…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Dejan Urošević , Bojan Arbutina , Dušan Onić

One of the main features of astrophysical shocks is their ability to accelerate particles to extremely high energies. The leading acceleration mechanism, the diffusive shock acceleration is reviewed. It is demonstrated that its efficiency…

Astrophysics · Physics 2009-11-06 M. A. Malkov , P. H. Diamond

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

We present results of semi-analytic calculations which show clear evidence for changes in the non-equilibrium ionization behind a supernova remnant forward shock undergoing efficient diffusive shock acceleration (DSA). The efficient…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Daniel J. Patnaude , Donald C. Ellison , Patrick Slane

Particle acceleration in relativistic shocks is studied analytically in the test-particle, small-angle scattering limit, for an arbitrary velocity-angle diffusion function D. Accurate analytic expressions for the spectral index s are…

Astrophysics · Physics 2008-11-26 Uri Keshet

Most recent extragalactic models of gamma-ray bursts consider the expansion of a relativistic blast wave, emanating from a solar-mass type progenitor, into the surrounding interstellar medium as the site for their activity. The popular…

Astrophysics · Physics 2007-05-23 Matthew G. Baring

The understanding of the particle spectra resulting from acceleration in relativistic shocks as they occur in extragalactic sources, is essential for the interpretation of the cosmic ray spectrum above the ankle ($E_p>3\cdot 10^{18}$ eV).…

Astrophysics · Physics 2007-08-13 A. Meli , J. Becker , J. J. Quenby , J. Luenemann