相关论文: Particle acceleration at ultrarelativistic shocks:…
We investigate effects of upstream density fluctuations on the diffusive shock acceleration by Monte Carlo simulations. The simulations show that particles are reaccelerated in the shock downstream region by a sound wave generated at the…
The radiative acceleration of particles and the electrostatic potential fields that arise in low density plasmas hit by radiation produced by a transient, compact source are investigated. We calculate the dynamical evolution and asymptotic…
To undergo diffusive shock acceleration, electrons need to be pre-accelerated to increase their energies by several orders of magnitude, else their gyro-radii are smaller than the finite width of the shock. In oblique shocks, where the…
We investigate the physics of particle acceleration at non-relativistic shocks exploiting two different and complementary approaches, namely a semi-analytic modeling of cosmic-ray modified shocks and large hybrid (kinetic protons/fluid…
We consider particle acceleration to high energy via diffusive shock acceleration in a simple, self-consistent shock in jet model for blazars. Electrons are assumed to be accelerated at a shock front in relativistic jets and radiate…
The structure of relativistic radiation mediated shocks (RRMS) propagating into a cold electron-proton plasma is calculated and analyzed. A qualitative discussion of the physics of relativistic and non relativistic shocks, including order…
Diffusive shock acceleration (DSA) by relativistic shocks is thought to generate the $dN/dE\propto E^{-p}$ spectra of charged particles in various astronomical relativistic flows. We show that for test particles in one dimension (1D),…
Supernova remnants are expected to contain braided (or stochastic) magnetic fields, which are in some regions directed mainly perpendicular to the shock normal. For particle acceleration due to repeated shock crossings, the transport in the…
Strong magnetically dominated Alfv\'enic turbulence is an efficient engine of non-thermal particle acceleration in a relativistic collisionless plasma. We argue that in the limit of strong magnetization, the type of energy distribution…
The relativistic wind of obliquely-rotating pulsars consists of toroidal stripes of opposite magnetic field polarity, separated by current sheets of hot plasma. By means of two- and three-dimensional particle-in-cell simulations, we…
Thermal electrons cannot directly participate in the process of diffusive acceleration at electron-ion shocks because their Larmor radii are smaller than the shock transition width: this is the well-known electron injection problem of…
The past decade has seen an outstanding development of nonthermal particle acceleration in magnetic reconnection in magnetically-dominated systems, with clear signatures of power-law energy distributions as a common outcome of…
In turbulent magnetized plasmas, charged particles can be accelerated to high energies through their interactions with the turbulent motions. As they do so, they draw energy from the turbulence, possibly up to the point where they start…
Plasma outflows from gamma-ray bursts (GRB), pulsar winds, relativistic jets, and ultra-intense laser targets radiate high energy photons. However, radiation damping is ignored in conventional PIC simulations. In this letter, we study the…
Shocks in astrophysical fluids can generate suprathermal particles by first order (or diffusive) Fermi acceleration. In the test particle regime there is a simple relation between the spectrum of the accelerated particles and the jump…
Relativistic current sheets have been proposed as the sites of dissipation in pulsar winds, jets in active galaxies and other Poynting-flux dominated flows. It is shown that the steady versions of these structures differ from their…
We study the acceleration of electrons and positrons at an electromagnetically modified, ultra-relativistic shock in the context of pulsar wind nebulae (PWNe). We simulate the outflow produced by an obliquely rotating pulsar in proximity of…
The analytical theory of diffusive cosmic ray acceleration at parallel stationary shock waves with magnetostatic turbulence is generalized to arbitrary shock speeds $V_s=\beta_1c$, including in particular relativistic speeds. This is…
The relations among the components of the exit momenta of ultrarelativistic electrons scattered on a strong electromagnetic wave of a low (optical) frequency and linear polarization are established using the exact solutions to the equations…
We calculate the proton distribution function due to heating by subsonic (Alfvenic) turbulence in a weakly magnetized collisionless plasma. The distribution function is nonthermal. For non-relativistic energies, it is an exponential of the…