Related papers: Nonthermal electron acceleration in turbulent post…
Flaring release of magnetic energy in solar corona is only possible if the magnetic field deviates from a potential one. We show that the linear MHD modes excited on top of the non-potential magnetic field possess a nonzero kinetic…
During solar flares, a large fraction of the released magnetic energy is carried by energetic electrons that transfer and deposit energy in the Sun's atmosphere. Electron transport is often approximated by a cold thick-target model (CTTM),…
Aims: We quantify the effects of twisted magnetic fields on the development of the magnetic Kelvin-Helmholtz instability (KHI) in transversely oscillating coronal loops. Methods: We modelled a fundamental standing kink mode in a straight,…
Solar flares are efficient particle accelerators with a large fraction of released magnetic energy (10-50%) converted into energetic particles such as hard X-ray producing electrons. This energy transfer process is not well constrained,…
We propose that non-thermal electrons are efficiently accelerated by first-order Fermi process at the fast shock, as a natural consequence of the new magnetohydrodynamic picture of the flaring region revealed with Yohkoh. An oblique fast…
Hard X-ray (HXR) sources are frequently observed near the top of solar flare loops, and the emission is widely ascribed to bremsstrahlung. We here revisit an alternative scenario which stresses the importance of inverse Compton processes…
Turbulent plasma motion is common in the universe, and invoked in solar flares to drive effective acceleration leading to high energy electrons. Unresolved mass motions are frequently detected in flares from extreme ultraviolet (EUV)…
Twisted coronal loops should be ubiquitous in the solar corona. Twisted magnetic fields contain excess magnetic energy, which can be released during magnetic reconnection, causing solar flares. The aim of this work is to investigate…
The relaxation of field-line tension during magnetic reconnection gives rise to a universal Fermi acceleration process involving the curvature drift of particles. However, the efficiency of this mechanism is limited by the trapping of…
Solar flares effectively accelerate particles to non-thermal energies. These accelerated electrons are responsible for energy transport and subsequent emissions in HXR, radio, and UV/EUV radiation. Due to the steeply decreasing electron…
We develop a model of particle energization and emission from strongly turbulent black-hole coronae. Our local model is based on a set of 2D radiative particle-in-cell simulations with an electron-ion plasma composition, injection and…
We investigate heating and acceleration of protons from a thermal gas with a generic diffusion and acceleration model, and subject to Coulomb scattering and energy loss, as was carried out in Petrosian & East (2008) for electrons. As…
The standard flare model, despite its success, is limited in comprehensively explaining the various processes involving nonthermal particles. One such missing ingredient is a detailed understanding of the various processes involved during…
In this paper we investigate the feasibility of bremsstrahlung radiation from `nonthermal' electrons as a source of hard X-rays from the intracluster medium of clusters of galaxies. With an exact treatment of the Coulomb collisions in a…
Nonthermal features are ubiquitously observed in electron velocity distribution functions in the solar wind, yet their origin in the collisionless, turbulent, expanding solar-wind plasma remains unclear. We investigate how solar-wind…
Magnetohydrodynamic kink waves naturally form as a consequence of perturbations to a structured medium, for example transverse oscillations of coronal loops. Linear theory has provided many insights in the evolution of linear oscillations,…
A fundamental problem in astrophysics is the interaction between magnetic turbulence and charged particles. It is now possible to use \emph{Ramaty High Energy Solar Spectroscopic Imager (RHESSI)} observations of hard X-rays (HXR) emitted by…
We investigate the acceleration of charged particles (both electrons and protons) at collisionless shocks predicted to exist in the vicinity of solar flares. The existence of standing termination shocks has been examined by flare models and…
We study the behaviour of shocked wind-electrons leaving wind-driving stars after undergoing the outer wind termination shock. As an example, we describe the evolution of the keV-energetic electron distribution function downstream of the…
Observational aspects of solar flares relevant to the acceleration process of electrons and protons are reviewed and it is shown that most of these observations can be explained by the interaction with flare plasma of a power law energy…