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Colliding collisionless shocks appear in a great variety of astrophysical phenomena and are thought to be possible sources of particle acceleration in the Universe. To investigate the detailed dynamics of this phenomenon, we have performed…

Intense laser-plasma interactions are an essential tool for the laboratory study of ion acceleration at a collisionless shock. With two-dimensional particle-in-cell calculations of a multicomponent plasma we observe two electrostatic…

Astrophysical shocks are often studied in the high Mach number limit but weakly compressive fast shocks can occur in magnetic reconnection outflows and are considered to be a site of particle energization in solar flares. Here we study the…

Solar and Stellar Astrophysics · Physics 2012-06-26 Jaehong Park , Jared C. Workman , Eric G. Blackman , Chuang Ren , Robert Siller

The expansion of a magnetized high-pressure plasma into a low-pressure ambient medium is examined with particle-in-cell (PIC) simulations. The magnetic field points perpendicularly to the plasma's expansion direction and binary collisions…

Plasma Physics · Physics 2016-09-13 Mark Eric Dieckmann , Gianluca Sarri , Domenico Doria , Anders Ynnerman , Marco Borghesi

A direct numerical simulation of a strong relativistic collisionless shock propagating into an unmagnetized medium has been performed in two spatial dimensions. It is found that: (i) collisionless shock exists, (ii) particle acceleration is…

Astrophysics · Physics 2007-05-23 Andrei Gruzinov

Collisionless shocks are common features in space and astrophysical systems where supersonic plasma flows interact, such as in the solar wind, the heliopause, and supernova remnants. Recent experimental capabilities and diagnostics allow…

Magnetized collisionless shocks drive particle acceleration broadly in space and astrophysics. We perform the first large-scale particle-in-cell simulations with realistic laboratory parameters (density, temperature, and velocity) to…

Plasma Physics · Physics 2024-05-24 P. Liu , D. Wu , D. W. Yuan , G. Zhao , Z. M. Sheng , X. T. He , J. Zhang

Nonrelativistic electrostatic unmagnetized shocks are frequently observed in laboratory plasmas and they are likely to exist in astrophysical plasmas. Their maximum speed, expressed in units of the ion acoustic speed far upstream of the…

Plasma Physics · Physics 2015-06-15 ME Dieckmann , H Ahmed , G Sarri , D Doria , I Kourakis , L Romagnani , M Pohl , M Borghesi

It is shown that collisionless shock waves can be driven in unmagnetized electron-positron plasmas by performing a two-dimensional particle-in-cell simulation. At the shock transition region, strong magnetic fields are generated by a…

Astrophysics · Physics 2008-03-31 Tsunehiko N. Kato

Shock waves in plasmas can be characterized by the mechanisms behind their formation. When binary collisions are frequent, dissipation is collision-driven and the shock width is a few mean free paths. In contrast, collisionless shocks rely…

Plasma Physics · Physics 2025-08-18 Yossef Nissim Kindi , Asaf Pe'er , Antoine Bret , Luís O. Silva , Kevin M. Schoeffler

Collisionless plasma shocks are a common feature of many space and astrophysical systems and are sources of high-energy particles and non-thermal emission, channeling as much as 20\% of the shock's energy into non-thermal particles. The…

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

In this paper, we study shock structures of collisionless shocks in partially ionized plasmas by means of two-dimensional hybrid simulations, where the shock is a perpendicular shock with shock velocity Vsh ~ 40 Va ~ 1333 km/s and the…

High Energy Astrophysical Phenomena · Physics 2016-02-03 Yutaka Ohira

Collisionless shocks play an important role in space and astrophysical plasmas by irreversibly converting the energy of the incoming supersonic plasma flows into other forms, including plasma heat, particle acceleration, and electromagnetic…

Collisionless shock waves are one of the main forms of energy conversion in space plasmas. They can directly or indirectly drive other universal plasma processes such as magnetic reconnection, turbulence, particle acceleration and wave…

We study processes at the transition region between hot (rare) and cold (dense) plasma in the collisionless regime. We use a 3-dimensional electromagnetic particle-in-cell (3-D PIC) relativistic code. Motivated by the transition region in…

Solar and Stellar Astrophysics · Physics 2017-09-25 Marian Karlicky , Frantisek Karlicky

The expansion of a thermal pressure-driven radial blast shell into a dilute ambient plasma is examined with two-dimensional PIC simulations. The purpose is to determine if laminar shocks form in a collisionless plasma that resemble their…

Plasma Physics · Physics 2018-05-30 M E Dieckmann , Q Moreno , D Doria , L Romagnani , G Sarri , D Folini , R Walder , A Bret , E d'Humieres , M Borghesi

Two charge- and current neutral plasma beams are modelled with a one-dimensional PIC simulation. The beams are uniform and unbounded. The relative speed between both beams is 0.4c. One beam is composed of electrons and protons and one out…

Astrophysics · Physics 2014-11-18 M E Dieckmann , A Bret

Within the context of Magnetohydrodynamics (MHD), the properties of a parallel shock do not depend on the field strength, as the field and the fluid are disconnected for such a geometry. However, in the collisionless case, the field can…

Plasma Physics · Physics 2021-08-25 Antoine Bret

We explore the physics of shock evolution and particle acceleration in non-relativistic collisionless shocks using multidimensional hybrid simulations. We analyze a wide range of physical parameters relevant to the acceleration of cosmic…

High Energy Astrophysical Phenomena · Physics 2015-05-28 L. Gargaté , A. Spitkovsky