Related papers: Acceleration of Energetic Particles Through Self-G…
Particle acceleration at astrophysical shocks may be very efficient if magnetic scattering is self-generated by the same particles. This nonlinear process adds to the nonlinear modification of the shock due to the dynamical reaction of the…
Context: Acceleration in coronal mass ejection driven shocks is currently considered the primary source of large solar energetic particle events. Aims: The solar wind, which feeds shock-accelerated particles, includes numerous ion…
Context. Solar energetic particles observed in association with coronal mass ejections (CMEs) are produced by the CME-driven shock waves. The acceleration of particles is considered to be due to diffusive shock acceleration (DSA). Aims. We…
We herein investigate shock formation and particle acceleration processes for both protons and electrons in a quasi-parallel high-Mach-number collisionless shock through a long-term, large-scale particle-in-cell simulation. We show that…
Counterpropagating Alfv\'en waves are ubiquitously observed in many astrophysical environments, such as a star surface and a planetary foreshock. We discuss an efficient particle acceleration mechanism in two counterpropagating circularly…
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…
We use 2.5-D electromagnetic particle-in-cell simulation code to investigate the acceleration of electrons in solar coronal holes through the interaction of Alfv\'en waves with an interplume region. The interplume is modeled by a cavity…
We report studies on first-order Fermi acceleration in parallel modified shock waves with a large scattering center compression ratio expected from turbulence transmission models. Using a Monte Carlo technique we have modeled particle…
In this work we used Particle-In-Cell simulations to study the interaction of circularly polarised Alfv\'en waves with one dimensional plasma density inhomogeneities transverse to the uniform magnetic field (phase mixing) in collisionless…
The linear theory of shock acceleration predicts the maximum particle energy to be limited only by the acceleration time and the size of the shock. We study the combined effect of acceleration nonlinearity (shock modification by accelerated…
We introduce a Monte Carlo model of nonlinear diffusive shock acceleration allowing for the generation of large-amplitude magnetic turbulence. The model is the first to include strong wave generation, efficient particle acceleration to…
We consider the recently discovered \emph{pair-Alfv\'en shock wave} occurring in collisionless electron-positron plasmas. We perform a series of Particle-In-Cell studies in one and two dimensions in order to determine the stability…
Extreme ultraviolet (EUV) waves are global waves in the solar corona which can accelerate particles. The efficiency of the acceleration depends on local plasma characteristics e.g. Alfv\'en speed and the geometry of the magnetic field. This…
The theory of shock acceleration predicts the maximum particle energy to be limited only by the acceleration time and the size (geometry) of the shock. This led to optimistic estimates for the galactic cosmic ray energy achievable in the…
We present numerical modelling of particle acceleration at coronal shocks propagating through a streamer-like magnetic field by solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show…
Non-detection of $\gamma$-ray emission from galaxy clusters has challenged diffusive shock acceleration (DSA) of cosmic-ray (CR) protons at weak collisionless shocks that are expected to form in the intracluster medium. As an effort to…
Dispersive Alfven waves (DAWs) offer, an alternative to magnetic reconnection, opportunity to accelerate solar flare particles. We study the effect of DAW polarisation, L-, R-, circular and elliptical, in different regimes inertial and…
In the Earth auroral zone, the electron acceleration by Alfv\'en waves is sometimes a precursor of the non-propagating acceleration structures. In order to investigate how Alfv\'en waves could generate non-propagating electric fields, a…
We present simulation results of the impulsively generated linear and non-linear Alfv\'en waves in the weakly curved coronal magnetic flux-tubes (coronal funnels) and discuss their implications for the coronal heating and solar wind…
Relativistic sources, e.g. gamma-ray bursts, pulsar wind nebulae and powerful active galactic nuclei produce relativistic outflows that lead to the formation of collisionless shock waves, where particle acceleration is thought to take…