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A collisionless shock may be strongly modified by the presence of neutral atoms through the processes of charge exchange between ions and neutrals and ionization of the latter. These two processes lead to exchange of energy and momentum…

High Energy Astrophysical Phenomena · Physics 2015-06-04 P. Blasi , G. Morlino , R. Bandiera , E. Amato , D. Caprioli

Relativistic collisionless shocks are associated with efficient particle acceleration when propagating into weakly magnetized homogeneous media; as the magnetization increases, particle acceleration becomes suppressed. We demonstrate that…

High Energy Astrophysical Phenomena · Physics 2023-04-26 Camilia Demidem , Joonas Nättilä , Alexandra Veledina

A one-dimensional particle-in-cell (PIC) simulation tracks a fast magnetosonic shock over time scales comparable to an inverse ion gyrofrequency. The magnetic pressure is comparable to the thermal pressure upstream. The shock propagates…

Plasma Physics · Physics 2018-08-01 Q. Moreno , M. E. Dieckmann , X. Ribeyre , E. d'Humières

We observe shock-front separation and species-dependent shock widths in multi-ion-species collisional plasma shocks, which are produced by obliquely merging plasma jets of a He/Ar mixture (97% He and 3% Ar by initial number density) on the…

Plasma Physics · Physics 2020-04-03 Tom Byvank , Samuel J. Langendorf , Carsten Thoma , Scott C. Hsu

We present two-dimensional hybrid kinetic/magnetohydrodynamic simulations of planned laser-ablation experiments in the Large Plasma Device (LAPD). Our results, based on parameters which have been validated in previous experiments, show that…

Plasma Physics · Physics 2016-12-21 M. S. Weidl , D. Winske , F. Jenko , C. Niemann

A full particle simulation study is carried out for studying microinstabilities generated at the shock front of perpendicular collisionless shocks. The structure and dynamics of shock waves are determined by Alfven Mach number and plasma…

Plasma Physics · Physics 2015-06-04 Takayuki Umeda , Yoshitaka Kidani , Shuichi Matsukiyo , Ryo Yamazaki

Relativistic collisionless shocks are believed to be efficient particle accelerators. Nonlinear outcome of the interaction of accelerated particles that run ahead of the shock, the so-called "precursor", with the unperturbed plasma of the…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Ehud Nakar , Antoine Bret , Milos Milosavljevic

We review recent progress on collisionless relativistic shocks. Kinetic instability theory is briefed including its predictions and limitations. The main focus is on numerical experiments in (i) pair and (ii) electron-nucleon plasmas. The…

High Energy Astrophysical Phenomena · Physics 2011-10-20 A. M. Bykov , R. A. Treumann

In this review we discuss some observational aspects and theoretical models of astrophysical collisionless shocks in partly ionized plasma with the presence of non-thermal components. A specific feature of fast strong collisionless shocks…

High Energy Astrophysical Phenomena · Physics 2015-06-15 A. M. Bykov , M. A. Malkov , J. C. Raymond , A. M. Krassilchtchikov , A. E. Vladimirov

In this work, we investigate collisionless shocks propagating in a relativistically hot unmagnetized electron-positron plasmas. We estimate the dissipation fraction at shocks in the relativistically hot plasma, showing that it is…

High Energy Astrophysical Phenomena · Physics 2024-10-21 Kamiido Kazuki , Ohira Yutaka

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

Laser-ablated high-energy-density (HED) plasmas offer a promising route to study astrophysically relevant processes underlying collisionless shock formation, magnetic field amplification, and particle acceleration in the laboratory. Using…

Plasma Physics · Physics 2021-05-26 Anna Grassi , Frederico Fiuza

Collisionless shocks are complex nonlinear structures that are not yet fully understood. In particular, the interaction between these shocks and the particles they accelerate remains elusive. Based on an instability analysis that relates…

Plasma Physics · Physics 2024-12-18 Antoine Bret , Asaf Pe'er

The properties of collisionless shocks are frequently assessed in the magnetohydrodynamics (MHD) model. Yet, in a collisionless plasma, an ambient magnetic field can sustain a stable anisotropy in the upstream or the downstream, resulting…

Plasma Physics · Physics 2023-03-08 Antoine Bret

The role of slow-mode MHD shocks in magnetic reconnection is one of great importance for energy conversion and transport, but in many astrophysical plasmas the plasma is not fully ionised. In this paper, we investigate, using numerical…

Solar and Stellar Astrophysics · Physics 2016-10-27 Andrew Hillier , Shinsuke Takasao , Naoki Nakamura

Shockwaves in plasma are usually dealt with using Magnetohydrodynamics (MHD). Yet, MHD entails the assumption of a short mean free path, which is not fulfilled in a collisionless plasma. Recently, for pair plasmas, we devised a model…

Plasma Physics · Physics 2023-01-04 Antoine Bret , Ramesh Narayan

A case of two interpenetrating, cold and quasi-neutral ion-electron plasmas is investigated with the multi-fluid approach. We consider that one plasma flows quasi-parallel to the lines of a background magnetic field embedded in another…

High Energy Astrophysical Phenomena · Physics 2019-03-19 Vladimir Zekovic

Collisionless shocks in plasmas play an important role in space physics (Earth's bow shock) and astrophysics (supernova remnants, relativistic jets, gamma-ray bursts, high energy cosmic rays). While the formation of a fluid shock through…

Plasma Physics · Physics 2015-06-22 Antoine Bret , Anne Stockem , Ramesh Narayan , Luis O. Silva

Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks,…

We explore analytically the structure of relativistic shock and solitary wave solutions in collisionless plasmas. In the wave frame of reference, a cold plasma is flowing from one end and impacting on a low velocity plasma. First we show…

Astrophysics · Physics 2007-05-23 David Medvigy , Abraham Loeb