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The stability of the cosmic ray modified shock (CRMS) is studied by means of numerical simulations. Owing to the nonlinear feedback of cosmic-ray (CR) acceleration, a downstream state of the modified shock can no longer be uniquely…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Tatsuhiko Saito , Masahiro Hoshino , Takanobu Amano

Context. The influence of magnetic fields on stellar core collapse and explosion is not well explored. It depends on the possibility to amplify the pre-collapse fields. Without rotation this can happen by compression, convection, the…

Solar and Stellar Astrophysics · Physics 2015-03-17 Martin Obergaulinger , Hans-Thomas Janka

A novel collisionless shock jump condition is suggested by modeling the entropy production at the shock transition region. We also calculate downstream developments of the atomic ionization balance and the ion temperature relaxation in…

High Energy Astrophysical Phenomena · Physics 2022-07-27 Jiro Shimoda , Yutaka Ohira , Aya Bamba , Yukikatsu Terada , Ryo Yamazaki , Tsuyoshi Inoue , Shuta J. Tanaka

We demonstrate that cosmic rays form filamentary structures in the precursors of supernova remnant shocks due to their self-generated magnetic fields. The cosmic-ray filamentation results in the growth of a long wavelength instability, and…

High Energy Astrophysical Phenomena · Physics 2015-05-30 B. Reville , A. R. Bell

Nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants is employed to calculate CR spectra. The magnetic field in SNRs is assumed to be significantly amplified by the efficiently accelerating nuclear CR component. It…

Astrophysics · Physics 2009-11-13 E. G. Berezhko , H. J. Voelk

There are two distinct breaks in the cosmic ray (CR) spectrum: the so-called "knee" around $3 \times 10^{15}$ eV and the so-called "ankle" around $10^{18}$ eV. Diffusive shock acceleration (DSA) at supernova remnant (SNR) shock fronts is…

High Energy Astrophysical Phenomena · Physics 2017-01-25 Chad Bustard , Ellen G. Zweibel , Cory Cotter

It has been long believed that oblique and quasi-perpendicular configurations in supernova remnants (SNRs) were inefficient at injecting ions into diffusive shock acceleration (DSA), and that the highest energy Galactic cosmic rays (CRs)…

High Energy Astrophysical Phenomena · Physics 2024-02-05 Emily Simon , Damiano Caprioli , Colby Haggerty , Brian Reville

Despite being studied for many years, the structure of collisionless shocks is still not fully determined. Such shocks are known to be accelerators of cosmic rays, which, in turn, modify the shock structure. The shock width $\lambda$ is…

High Energy Astrophysical Phenomena · Physics 2024-05-15 Antoine Bret , Asaf Pe'er

We present an interpretation of the time variability of the $X$-ray flux recently reported from a multi-epoch campaign of $15$ years observations of the supernova remnant Cassiopeia A by {\it Chandra}. We show for the first time…

High Energy Astrophysical Phenomena · Physics 2018-06-27 F. Fraschetti , S. Katsuda , T. Sato , J. R. Jokipii , J. Giacalone

Galactic cosmic rays (CR) are particles presumably accelerated in supernova remnant shocks that propagate in the interstellar medium up to the densest parts of molecular clouds, losing energy and their ionisation efficiency because of the…

High Energy Astrophysical Phenomena · Physics 2016-05-25 M. Padovani , A. Marcowith , P. Hennebelle , K. Ferrière

We present very-high-resolution 1D MHD simulations of the late-stage supernova remnants (SNR). In the post-adiabatic stage the magnetic field has an important and significant dynamical effect on the shock dynamics, the flow structure, and…

High Energy Astrophysical Phenomena · Physics 2018-07-18 O. Petruk , T. Kuzyo , S. Orlando , M. Pohl , M. Miceli , F. Bocchino , V. Beshley , R. Brose

We investigate shock acceleration in a realistic astrophysical environment with density inhomogeneities. The turbulence induced by the interaction of the shock precursor with upstream density fluctuations amplifies both upstream and…

High Energy Astrophysical Phenomena · Physics 2022-02-02 Siyao Xu , Alex Lazarian

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

We investigate the theoretical and observational implications of the acceleration of protons and heavier nuclei in supernova remnants (SNRs). By adopting a semi-analytical technique, we study the non-linear interplay among particle…

High Energy Astrophysical Phenomena · Physics 2017-08-23 D. Caprioli , P. Blasi , E. Amato

A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants is employed to investigate the properties of the remnant SN 1987A. It is shown that a large downstream magnetic field ~10 mG is required to fit the existing…

Astrophysics · Physics 2009-11-11 E. G. Berezhko , L. T. Ksenofontov

We show here that highly polarized X-ray synchrotron radiation from young supernova remnants (SNRs) can be modeled within the framework of diffusive shock acceleration (DSA) and nonlinear magnetic turbulence generation.Cosmic ray…

High Energy Astrophysical Phenomena · Physics 2024-09-30 Andrei. M. Bykov , Sergei. M. Osipov , Yury. A. Uvarov , Donald. C. Ellison , Patrick Slane

The process of cosmic ray first-order Fermi acceleration at relativistic shock waves is studied with the method of Monte Carlo simulations. The simulations are based on numerical integration of particle equations of motion in a turbulent…

Astrophysics · Physics 2009-11-10 Jacek Niemiec , Michal Ostrowski

We present evidence for cosmic ray acceleration at the forward shock in Tycho's supernova remnant (SNR) from three X-ray observables: (1) the proximity of the contact discontinuity to the forward shock, or blast wave, (2) the morphology of…

While supernova remnants (SNRs) have long been considered prime candidates for the source of cosmic rays, at least to energies up to ~10^14 eV, it is only over the past several years that direct evidence of such energetic particles in SNRs…

Astrophysics · Physics 2007-05-23 Patrick Slane

The present article investigates magnetic amplification in the upstream medium of SNR blast wave through both resonant and non-resonant regimes of the streaming instability. It aims at a better understanding of the diffusive shock…

High Energy Astrophysical Phenomena · Physics 2015-05-14 A. Marcowith , F. Casse