相关论文: Ion-electron instabilities in the precursor of wea…

Fermi acceleration can develop efficiently at relativistic collisionless shock waves provided the upstream (unshocked) plasma is weakly magnetized. At low magnetization, the large size of the shock precursor indeed provides enough time for…

We investigate the physics of quasi-parallel trans-relativistic shocks propagating in weakly magnetized plasmas by means of long-duration two-dimensional particle-in-cell simulations. The structure of the shock precursor is shaped by a…

It is argued and demonstrated by particle-in-cell simulations that the synchrotron maser instability could develop at the front of a relativistic, magnetized shock. The instability generates strong low-frequency electromagnetic waves…

We examine the electron-ion streaming instabilities driven by drift velocities of the order of the electron thermal velocity in a nonmagnetized plasma by one-dimensional electrostatic particle-in-cell code which adopts an ion-to-electron…

Collisionless shocks are common in astrophysical systems and stand as sites of particle acceleration. While particles at perpendicular shocks may not return to the upstream region, at oblique shocks a fraction of energetic electrons manage…

A two-dimensional electromagnetic particle-in-cell simulation with the realistic ion-to-electron mass ratio of 1836 is carried out to investigate the electrostatic collisionless shocks in relatively high-speed (~3000 km s^-1) plasma flows…

Electron acceleration associated with various plasma kinetic instabilities in a nonrelativistic, very-high-Alfv\'en Mach-number ($M_A \sim 45$) shock is revealed by means of a two-dimensional fully kinetic PIC simulation. Electromagnetic…

The growth and saturation of Buneman-type instabilities is examined with a particle-in-cell (PIC) simulation for parameters that are representative for the foreshock region of fast supernova remnant (SNR) shocks. A dense ion beam and the…

We perform particle-in-cell simulations of perpendicular nonrelativistic collisionless shocks to study electron heating and pre-acceleration for parameters that permit extrapolation to the conditions at young supernova remnants. Our…

We investigated electromagnetic precursor wave emission in relativistic shocks by using two-dimensional particle-in-cell simulations. We found that the wave amplitude is significantly enhanced by a positive feedback process associated with…

(Abridged) This paper addresses the issue of magnetic field generation in a relativistic shock precursor through micro-instabilities. The level of magnetization of the upstream plasma turns out to be a crucial parameter, notably because the…

Mildly relativistic shocks in magnetized electron-ion plasmas are investigated with 2D kinetic particle-in-cell simulations of unprecedentedly high resolution and large scale for conditions that may be found at internal shocks in blazar…

Weakly magnetized shock waves are paramount to a large diversity of environments, including supernova remnants, blazars, and binary-neutron-star mergers. Understanding the distribution of energy between electrons and ions within these…

Plasma instabilities (e.g., Buneman, Weibel and other two-stream instabilities) created in collisionless shocks may be responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle…

Observation of low- and high-frequency backward waves in the nonlinear regime of the Buneman instability is reported. Intense low-frequency backward waves propagating in the direction opposite to the electron drift (with respect to the ion…

A two-dimensional particle-in-cell simulation is performed to investigate weakly magnetized perpendicular shocks with a magnetization parameter of 6 x 10^-5, which is equivalent to a high Alfv\'en Mach number M_A of ~130. It is shown that…

The evolution of the Buneman and two-stream instabilities driven by a cold dilute mildly relativistic electron beam is studied as a function of the ion\'\s charge-to-mass ratio. The growth rates of both instabilities are comparable for the…

Electrostatic behavior of a collisionless plasma in the foot region of high Mach number perpendicular shocks is investigated through the two-dimensional linear analysis and electrostatic particle-in-cell (PIC) simulation. The simulations…

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…

The study of collisionless shocks and their role in cosmic-ray acceleration has gained increasing importance through both observations and simulations. Accurately modeling the shock transition region, where particle injection occurs,…