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In this second paper of a series, we discuss the dynamics of a plasma entering the precursor of an unmagnetized, relativistic collisionless pair shock. We discuss how this background plasma is decelerated and heated through its interaction…

High Energy Astrophysical Phenomena · Physics 2019-10-02 M. Lemoine , A. Vanthieghem , G. Pelletier , L. Gremillet

A high-fidelity simulation of the shock/transitional boundary layer interaction caused by a 15-degrees axisymmetrical compression ramp is performed at a freestream Mach number of 5 and a transitional Reynolds number. The inlet of the…

Fluid Dynamics · Physics 2020-11-18 Mathieu Lugrin , Samir Beneddine , Colin Leclercq , Eric Garnier , Reynald Bur

Monte-Carlo computations for highly relativistic parallel shock particle acceleration are presented for upstream flow gamma factors, $\Gamma=(1-V_{1}^{2}/c^{2})^{-0.5}$ with values between 5 and $10^{3}$. The results show that the spectral…

Astrophysics · Physics 2009-11-07 A. Meli , J. J Quenby

The localized deposition of the energy of a laser pulse, as it ablates a solid target, introduces high thermal pressure gradients in the plasma. The thermal expansion of this laser-heated plasma into the ambient medium (ionized residual…

Plasma Physics · Physics 2009-11-30 M E Dieckmann , G Sarri , L Romagnani , I Kourakis , M Borghesi

Perpendicular collisionless shocks propagating into partially ionized plasmas are investigated by two-dimensional hybrid particle simulations. It is shown that some neutral particles leak into the upstream region from the downstream region,…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Yutaka Ohira

We present space- and time-resolved experimental data of head-on-merging, supersonic plasma jets (of an argon/impurity mixture) in an initially collisionless regime for counter-streaming ions. The merging begins with collisionless…

Plasma Physics · Physics 2015-05-04 Auna L. Moser , Scott C. Hsu

Observations of the interaction of an intense {\lambda}0 \approx 10 {\mu}m laser pulse with near-critical overdense plasmas (ne = 1.8 - 3 nc) are presented. For the first time, transverse optical probing is used to show a recession of the…

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…

Colliding hypersonic flows play a decisive role in many astrophysical objects. In this paper, we look at the idealized model of a 2D plane parallel isothermal slab (CDL) and at symmetric settings, where both flows have equal parameters. We…

Astrophysics · Physics 2009-11-11 Doris Folini , Rolf Walder

Plasma outflows from gamma-ray bursts, supernovae, and relativistic jets, in general, interact with the surrounding medium through collisionless shocks. The microphysics of such shocks are still poorly understood, which, potentially, can…

Astrophysics · Physics 2009-11-10 Christian Busk Hededal , Ken-Ichi Nishikawa

Using particle-in-cell simulations that label ions and electrons according to their initial inflow region, we find that during 2D collisionless magnetic reconnection, the bulk flow of the plasma from each inflow side crosses paths with…

We perform a numerical-simulation study of the acceleration of electrons at shocks that propagate through a prespecified, kinematically defined turbulent magnetic field. The turbulence consists of broadband magnetic fluctuations that are…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Fan Guo , Joe Giacalone

We investigate shock structure and particle acceleration in relativistic magnetized collisionless electron-ion shocks by means of 2.5D particle-in-cell simulations with ion-to-electron mass ratios (m_i/m_e) ranging from 16 to 1000. We…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Lorenzo Sironi , Anatoly Spitkovsky

The complex interaction between shocks and plasma turbulence is extremely important to address crucial features of energy conversion in a broad range of astrophysical systems. We study the interaction between a supercritical, perpendicular…

A study of collisionless external shocks in gamma-ray bursts is presented. The shock structure, electromagnetic fields, and process of electron acceleration are assessed by performing a self-consistent 3D particle-in-cell (PIC) simulation.…

High Energy Astrophysical Phenomena · Physics 2015-09-30 Kazem Ardaneh , Dongsheng Cai , Ken-Ichi Nishikawa , Bertrand Lembége

Perpendicular relativistic ($\gamma_0=10$) shocks in magnetized pair plasmas are investigated using two dimensional Particle-in-Cell simulations. A systematic survey, from unmagnetized to strongly magnetized shocks, is presented accurately…

High Energy Astrophysical Phenomena · Physics 2018-04-25 Illya Plotnikov , Anna Grassi , Mickael Grech

Most of the plasma microphysics which shapes the acceleration process of particles at collisionless shock waves takes place in the cosmic-ray precursor, through the interaction of accelerated particles with the unshocked plasma. Detecting…

High Energy Astrophysical Phenomena · Physics 2017-05-03 Ruben Zakine , Martin Lemoine

Shock related unsteadiness over axisymmetric spiked body configurations is experimentally investigated at a freestream supersonic Mach number of 2.0 at 0$^\circ$ angle of attack. Three different forebody configurations mounted with a sharp…

Fluid Dynamics · Physics 2020-08-04 Devabrata Sahoo , S. K. Karthick , Sudip Das , Jacob Cohen

We present results of 2D3V particle-in-cell simulations of non-relativistic plasma collisions with absent or parallel large-scale magnetic field for parameters applicable to the conditions at young supernova remnants. We study the collision…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Jacek Niemiec , Martin Pohl , Antoine Bret , Volkmar Wieland

Strong non-relativistic shocks are known to accelerate particles up to relativistic energies. However, for Diffusive Shock Acceleration electrons must have a highly suprathermal energy, implying a need for very efficient pre-acceleration.…

Plasma Physics · Physics 2023-10-24 Karol Fulat , Artem Bohdan , Gabriel Torralba Paz , Martin Pohl