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We perform two-dimensional relativistic magnetohydrodynamic simulations of a mildly relativistic shock propagating through an inhomogeneous medium. We show that the postshock region becomes turbulent owing to preshock density inhomogeneity,…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Yosuke Mizuno , Martin Pohl , Jacek Niemiec , Bing Zhang , Ken-Ichi Nishikawa , Philip E. Hardee

We present results from two-dimensional numerical simulations of a supersonic turbulent flow in the plane of the galactic disk, incorporating shear, thresholded and discrete star formation (SF), self-gravity, rotation and magnetic fields. A…

Astrophysics · Physics 2009-10-28 T. Passot , E. Vazquez-Semadeni , A. Pouquet

Galactic cosmic rays (CRs) are believed to be accelerated at supernova remnant (SNR) shocks. In the hadronic scenario the TeV gamma-ray emission from SNRs originates from decaying pions that are produced in collisions of the interstellar…

High Energy Astrophysical Phenomena · Physics 2020-06-24 Matteo Pais , Christoph Pfrommer , Kristian Ehlert , Maria Werhahn , Georg Winner

Galactic cosmic rays are believed to be accelerated at supernova remnants. However, whether supernova remnants can be Pevatrons is still very unclear. In this work we argue that PeV cosmic rays can be accelerated during the early phase of a…

High Energy Astrophysical Phenomena · Physics 2021-11-24 Tsuyoshi Inoue , Alexandre Marcowith , Gwenael Giacinti , Allard Jan van Marle , Shogo Nishino

Instabilities in relativistic magnetized jets are thought to be deeply connected to their energy dissipation properties and to the consequent acceleration of the non-thermal emitting relativistic particles. Instabilities lead to the…

High Energy Astrophysical Phenomena · Physics 2024-07-23 M. Musso , G. Bodo , G. Mamatsashvili , P. Rossi , A. Mignone

We conduct 3D magnetohydrodynamic (MHD) simulations of decaying turbulence in the solar wind context. To account for the spherical expansion of the solar wind, we implement the expanding box model. The initial turbulence comprises…

Solar and Stellar Astrophysics · Physics 2025-01-27 Chen Shi , Nikos Sioulas , Zesen Huang , Marco Velli , Anna Tenerani , Victor Réville

Cosmic ray (CR) transport and acceleration is essential for many astrophysical problems, e.g., CMB foreground, ionization of molecular clouds and all high energy phenomena. Recent advances in MHD turbulence call for revisions in the…

High Energy Astrophysical Phenomena · Physics 2011-12-06 Huirong Yan , A. Lazarian

Understanding cosmic ray (CR) diffusion in a partially ionized medium is both crucial and challenging. In this study, we investigate CR perpendicular superdiffusion and parallel transport in turbulent, partially ionized media using…

Astrophysics of Galaxies · Physics 2025-10-09 Yue Hu , Siyao Xu , Alex Lazarian , James M. Stone , Philip F. Hopkins

We investigate the long-time evolution of magnetic fields generated by the two-stream instability at ultra- and sub-relativistic astrophysical collisionless shocks. Based on 3D PIC simulation results, we introduce a 2D toy model of…

We report here on a fast current-driven instability at relativistic collisionless shocks, triggered by the perpendicular current carried by the supra-thermal particles as they gyrate around the background magnetic field in the shock…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Martin Lemoine , Guy Pelletier , Laurent Gremillet , Illya Plotnikov

Magnetic reconnection and non-thermal particle distributions associated with current-driven instabilities are investigated by means of resistive magnetohydrodynamics (MHD) simulations combined with relativistic test particle methods. We…

High Energy Astrophysical Phenomena · Physics 2017-04-19 Bart Ripperda , Oliver Porth , Chun Xia , Rony Keppens

This paper investigates the nature of the MHD turbulence excited by the streaming of accelerated cosmic rays in a shock wave precursor. The two recognised regimes (non-resonant and resonant) of the streaming instability are taken into…

Astrophysics · Physics 2009-11-11 Guy Pelletier , Martin Lemoine , Alexandre Marcowith

Using three-dimensional magnetohydrodynamics simulations, we show that the efficiency of cosmic-ray (CR) production at supernova remnants (SNRs) is over-predicted if it could be estimated based on proper motion measurements of H$\alpha$…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Jiro Shimoda , Tsuyoshi Inoue , Yutaka Ohira , Ryo Yamazaki , Aya Bamba , Jacco Vink

We derive analytically the vorticity generated downstream of a two-dimensional rippled hydromagnetic shock neglecting fluid viscosity and resistivity. The growth of the turbulent component of the downstream magnetic field is driven by the…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Federico Fraschetti

Measurements of solar wind turbulence reveal the ubiquity of discontinuities. In this study, we investigate how the discontinuities, especially rotational discontinuities (RDs), are formed in magnetohydrodynamic (MHD) turbulence. In a…

Solar and Stellar Astrophysics · Physics 2015-09-09 Liping Yang , Lei Zhang , Jiansen He , Chuanyi Tu , Linghua Wang , Eckart Marsch , Xin Wang , Shaohua Zhang , Xueshang Feng

Whether the magnetorotational instability (MRI) can amplify initially weak magnetic fields to dynamically relevant strengths in core collapse supernovae is still a matter of active scientific debate. Recent numerical studies have shown that…

Solar and Stellar Astrophysics · Physics 2016-06-03 Tomasz Rembiasz , Jérôme Guilet , Martin Obergaulinger , Pablo Cerdá-Durán , Miguel-Ángel Aloy , Ewald Müller

Collisionless plasma shocks are efficient sources of non-thermal particle acceleration in space and astrophysical systems. We use hybrid (kinetic ions -- fluid electrons) simulations to examine the non-linear feedback of the self-generated…

High Energy Astrophysical Phenomena · Physics 2020-12-16 Colby C. Haggerty , Damiano Caprioli

We present a first principles study of chiral plasma instabilities and the onset of chiral turbulence in QED plasmas far from equilibrium. By performing classical-statistical lattice simulations of the microscopic theory, we show that the…

High Energy Physics - Phenomenology · Physics 2020-08-06 Mark Mace , Niklas Mueller , Sören Schlichting , Sayantan Sharma

Core collapse supernovae (CCSNe) produce fast shocks which pervade the dense circum-stellar medium (CSM) of the stellar progenitor. Cosmic rays (CRs) if accelerated at these shocks can induce the growth of electromagnetic fluctuations in…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Alexandre Marcowith , Vikram Dwarkadas , Matthieu Renaud , Vincent Tatischeff , Gwenael Giacinti

We present the results obtained from linear stability analysis and 2.5-dimensional magnetohydrodynamic (MHD) simulations of the magnetorotational instability (MRI), including the effects of cosmic rays (CRs). We took into account of the CR…

High Energy Astrophysical Phenomena · Physics 2015-03-17 Takuhito Kuwabara , Chung-Ming Ko