English
Related papers

Related papers: Semi-analytic Models for Electron Acceleration in …

200 papers

The highly amplified magnetic fields suggested by observations of some supernova remnant (SNR) shells are most likely an intrinsic part of efficient particle acceleration by shocks. This strong turbulence, which may result from cosmic ray…

Astrophysics · Physics 2009-11-13 Andrey E. Vladimirov , Andrei M. Bykov , Donald C. Ellison

We perform particle-in-cell simulations of perpendicular nonrelativistic collisionless shocks to study electron heating and pre-acceleration for parameters that permit extrapolation to the conditions at young supernova remnants. Our…

High Energy Astrophysical Phenomena · Physics 2017-10-04 Artem Bohdan , Jacek Niemiec , Oleh Kobzar , Martin Pohl

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

We propose a semi-classical approach based on the Vlasov equation to describe the time-dependent electronic dynamics in a bulk simple metal under an ultrashort intense laser pulse. We include in the effective potential not only the ionic…

Plasma Physics · Physics 2021-09-08 Mizuki Tani , Tomohito Otobe , Yasushi Shinohara , Kenichi L. Ishikawa

Collisionless shock waves, found in supernova remnants, interstellar, stellar, and planetary environments, and laboratories, are one of nature's most powerful particle accelerators. This study combines in situ satellite measurements with…

High Energy Astrophysical Phenomena · Physics 2025-03-05 Savvas Raptis , Ahmad Lalti , Martin Lindberg , Drew L. Turner , Damiano Caprioli , James L. Burch

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

We present results from a fully relativistic Monte Carlo simulation of diffusive shock acceleration (DSA) in unmodified (i.e., test-particle) shocks. The computer code uses a single algorithmic sequence to smoothly span the range from…

Astrophysics · Physics 2007-05-23 Donald C. Ellison

The observed energy spectra of accelerated particles at interplanetary shocks often do not match the diffusive shock acceleration (DSA) theory predictions. In some cases, the particle flux forms a plateau over a wide range of energies,…

High Energy Astrophysical Phenomena · Physics 2024-10-29 Mikhail Malkov , Joe Giacalone , Fan Guo

We present results from a fully relativistic Monte Carlo simulation of diffusive shock acceleration (DSA) in unmodified shocks. The computer code uses a single algorithmic sequence to smoothly span the range from nonrelativistic speeds to…

Astrophysics · Physics 2009-11-10 Donald C. Ellison , Glen P. Double

Using large-scale fully-kinetic two-dimensional particle-in-cell simulations, we investigate the effects of shock rippling on electron acceleration at low-Mach-number shocks propagating in high-$\beta$ plasmas, in application to merger…

High Energy Astrophysical Phenomena · Physics 2021-10-04 Oleh Kobzar , Jacek Niemiec , Takanobu Amano , Masahiro Hoshino , Shuichi Matsukiyo , Yosuke Matsumoto , Martin Pohl

The radio spectra of many shell-type supernova remnants show deviations from those expected on theoretical grounds. In this paper we determine the effect of stochastic reacceleration on the spectra of electrons in the GeV band and at lower…

High Energy Astrophysical Phenomena · Physics 2015-01-28 M. Pohl , A. Wilhelm , I. Telezhinsky

Galaxy clusters are known to host many active galaxies (AGNs) with radio jets, which could expand to form radio bubbles with relativistic electrons in the intracluster medium (ICM). It has been suggested that fossil relativistic electrons…

High Energy Astrophysical Phenomena · Physics 2019-01-09 Hyesung Kang

Numerous astrophysical shock waves evolve in an environment where the radiative cooling behind the shock affects the hydrodynamical structure downstream, thereby influencing the potential for particle acceleration via diffusive shock…

High Energy Astrophysical Phenomena · Physics 2026-01-14 Pierre Cristofari

Thermal electrons cannot directly participate in the process of diffusive acceleration at electron-ion shocks because their Larmor radii are smaller than the shock transition width: this is the well-known electron injection problem of…

High Energy Astrophysical Phenomena · Physics 2022-06-29 Mohamad Shalaby , Rouven Lemmerz , Timon Thomas , Christoph Pfrommer

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

The early acceleration of protons and electrons in the nonrelativistic collisionless shocks with three obliquities are investigated through 1D particle-in-cell simulations. In the simulations, the charged particles possessing a velocity of…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Jun Fang , Chun-Yan Lu , Jing-Wen Yan , Huan Yu

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

The theory of diffusive acceleration of energetic particles at shock fronts assumes charged particles undergo spatial diffusion in a uniform magnetic field. If, however, the magnetic field is not uniform, but has a stochastic or braided…

Astrophysics · Physics 2007-05-23 J. G. Kirk , P. Duffy , Y. A. Gallant

Diffusive shock acceleration (DSA) at relativistic shocks is likely to be an important acceleration mechanism in various astrophysical jet sources, including radio-loud AGN. An important recent development for blazar science is the ability…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Matthew G. Baring , Markus Boettcher , Errol J. Summerlin

To undergo diffusive shock acceleration, electrons need to be pre-accelerated to increase their energies by several orders of magnitude, else their gyro-radii are smaller than the finite width of the shock. In oblique shocks, where the…

Plasma Physics · Physics 2022-06-08 Paul J. Morris , Artem Bohdan , Martin S. Weidl , Martin Pohl