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In this second paper in a series dedicated to characterizing shear layers via 2D hybrid (kinetic ions -- fluid electrons) simulations, we study the dynamical role of nonthermal particles (cosmic rays, CRs), either spontaneously generated or…

High Energy Astrophysical Phenomena · Physics 2026-04-15 Naixin Liang , Damiano Caprioli

The self-regulation of cosmic ray (CR) transport in the interstellar and intracluster media has long been viewed through the lenses of linear and quasilinear kinetic plasma physics. Such theories are believed to capture the essence of CR…

High Energy Astrophysical Phenomena · Physics 2019-09-04 Cole Holcomb , Anatoly Spitkovsky

We study diffusion of Cosmic Rays (CRs) in turbulent magnetic fields using test particle simulations. Electromagnetic fields are produced in direct numerical MHD simulations of turbulence and used as an input for particle tracing, particle…

Astrophysics of Galaxies · Physics 2015-05-18 A. Beresnyak , H. Yan , A. Lazarian

Diffusion of cosmic rays (CRs) is the key process of understanding their propagation and acceleration. We employ the description of spatial separation of magnetic field lines in MHD turbulence in Lazarian & Vishniac (1999) to quantify the…

High Energy Astrophysical Phenomena · Physics 2016-12-21 A. Lazarian , Huirong Yan

We investigate the Kelvin-Helmholtz instability occuring at the interface of a shear flow configuration in 2D compressible magnetohydrodynamics (MHD). The linear growth and the subsequent non-linear saturation of the instability are studied…

Astrophysics · Physics 2009-10-31 R. Keppens , G. Toth , R. H. J. Westermann , J. P. Goedbloed

Magnetic fields on the order of 100 $\mu$G observed in young supernova remnants cannot be amplified by shock compression alone. To investigate the amplification caused by turbulent dynamo, we perform three-dimensional MHD simulations of the…

Astrophysics of Galaxies · Physics 2022-12-28 Yue Hu , Siyao Xu , James M. Stone , Alex Lazarian

Fully kinetic two-dimensional particle-in-cell simulations are used to study electron acceleration at high-Mach-number nonrelativistic perpendicular shocks. SNR shocks are mediated by the Weibel instability which is excited because of an…

High Energy Astrophysical Phenomena · Physics 2020-04-15 Artem Bohdan , Martin Pohl , Jacek Niemiec , Sergei Vafin , Yosuke Matsumoto , Takanobu Amano , Masahiro Hoshino

Supernova remnants (SNRs) have long been assumed to be the source of cosmic rays (CRs) up to the "knee" of the CR spectrum at 10^15 eV, accelerating particles to relativistic energies in their blast waves by the process of diffusive shock…

Cosmic ray (CR) spectra, both measured upon their arrival at the Earth's atmosphere and inferred from the emission in supernova remnants (SNRs), appear to be significantly steeper than the "standard" diffusive shock acceleration (DSA)…

High Energy Astrophysical Phenomena · Physics 2019-11-06 Adrian Hanusch , Tatyana V. Liseykina , Mikhail Malkov , Felix Aharonian

Laser experiments are becoming established as a new tool for astronomical research that complements observations and theoretical modeling. Localized strong magnetic fields have been observed at a shock front of supernova explosions.…

We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a…

High Energy Astrophysical Phenomena · Physics 2015-06-16 K. M. Schure , A. R. Bell

The chiral magnetic effect emerges from a miroscopic level, and its interesting consequences have been discussed in the dynamics of the early universe, neutron stars and quark-gluon plasma. An instability is caused by anomalous electric…

High Energy Astrophysical Phenomena · Physics 2019-03-01 Yasufumi Kojima , Yuri Miura

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

A rapidly growing amount of evidences, mostly coming from the recent gamma-ray observations of Galactic supernova remnants (SNRs), is seriously challenging our understanding of how particles are accelerated at fast shocks. The cosmic-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Damiano Caprioli

We consider a recently discovered class of instabilities, driven by cosmic ray streaming, in a variety of environments. We show that although these instabilities have been discussed primarily in the context of supernova driven interstellar…

Astrophysics of Galaxies · Physics 2014-11-20 Ellen G. Zweibel , John E. Everett

We study dynamical effects of cosmics rays (CRs) on the thermal instability in the linear regime. CRs and the thermal plasma are treated as two different interacting fluids, in which CRs can diffuse along the magnetic field lines. We show…

Solar and Stellar Astrophysics · Physics 2009-05-14 Mohsen Shadmehri

Kinetic diffusion of cosmic rays ahead of perpendicular shocks induces charge non-neutrality, which is mostly, yet not completely, screened by the bulk plasma via polarization drift current. Hydrodynamic shear instabilities as well as…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Maxim Lyutikov

Relativistic magnetized jets, such as those from AGN, GRBs and XRBs, are susceptible to current- and pressure-driven MHD instabilities that can lead to particle acceleration and non-thermal radiation. Here we investigate the development of…

It is shown that amplification of the magnetic field in supernova remnants (SNRs) occurs in all six objects where morphological measurements are presently available in the hard X-ray continuum at several keV. For the three archetypical…

Astrophysics · Physics 2008-11-26 H. J. Voelk , E. G. Berezhko , L. T. Ksenofontov

Fast reconnection in magnetically dominated plasmas is widely invoked in models of dissipation in pulsar winds, gamma-ray flares in the Crab nebula, and to explain the radio nanoshots of pulsars. When current sheets evolve reaching a…

High Energy Astrophysical Phenomena · Physics 2026-02-11 Vittoria Berta , Matteo Bugli , Andrea Mignone , Giancarlo Mattia , Luca Del Zanna , Stefano Truzzi
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