Related papers: Fast electron slowing-down and diffusion in a high…
Solar flares are explosive releases of magnetic energy stored in the solar corona, driven by magnetic reconnection. These events accelerate electrons, generating hard X-ray emissions and often display Quasi Periodic Pulsations (QPPs) across…
Coronae express different facets of their energy release processes in different wavelength regions. While soft X-ray and EUV emission dominates the radiative losses of the thermal plasma, hard X-ray emission (>10 keV) can be produced from…
The stochastic acceleration of subrelativistic electrons from a background plasma is studied in order to find a possible explanation of the hard X-ray (HXR) emission detected from the Coma cluster. We calculate the necessary energy supply…
Models for characterization of laser-accelerated electron via its produced bremsstrahlung are provided for both thin and thick targets. An effective temperature functional is proposed to overcome the so-called cold and hot "temperatures" in…
Aims: We investigate the electron acceleration in convective electric fields of cascading magnetic reconnection in a flaring solar corona and show the resulting hard X-ray (HXR) radiation spectra caused by Bremsstrahlung for the coronal…
Spectroscopic observations in X-ray wavelengths provide excellent diagnostics of the temperature distribution in solar flare plasma. The Solar X-ray Monitor (XSM) onboard the Chandrayaan-2 mission provides broad-band disk integrated soft…
X-ray and EUV observations are an important diagnostic of various plasma parameters of the solar atmosphere during solar flares. Soft X-ray and EUV observations often show coronal sources near the top of flaring loops, while hard X-ray…
Particle acceleration is one of the most significant features that are ubiquitous among space and cosmic plasmas. It is most prominent during flares in the case of the Sun, with which huge amount of electromagnetic radiation and high-energy…
Recent progress in solar Hard X-ray (HXR) observations with RHESSI data and methods for spectral inversion allow us to study model-independent mean electron flux spectra in solar flares. We report several hard X-ray events observed by…
The content of hot material in the corona is not constant. Soft X-ray and high-temperature EUV line observations show that new material, apparently heated and evaporated from the chromosphere, is frequently injected into the corona both in…
We identify a set of ~100 "cold" solar flares and perform a statistical analysis of them in the microwave range. Cold flares are characterized by a weak thermal response relative to nonthermal emission. This work is a follow up of a…
Hard X-ray (HXR) spectroscopy is the most direct method of diagnosing energetic electrons in solar flares. Here we present a technique which allows us to use a single HXR spectrum to determine an effectively stereoscopic electron energy…
We consider electron acceleration by obliquely propagating fast mode waves in magnetically dominated accretion disk coronae. For low coronal plasma densities, acceleration can exceed Coulomb drag at lower energies and energize electrons out…
One of the key problems in solar flare physics is the determination of the low-energy cut-off; the value that determines the energy of nonthermal electrons and hence flare energetics. We discuss different approaches to determine the…
We present a study of the spatial and spectral evolution of the loop-top (LT) sources in a sample of 6 flares near the solar limb observed by {\it RHESSI}. A distinct coronal source, which we identify as the LT source, was seen in each of…
We present an ordinary case in the momentum diffusion equation for the electron spectrum evolution and investigate the energy spectra and time dependent properties of flare in Mrk 421 in the frame of a time-dependent one-zone synchrotron…
Solar flare hard X-ray spectra from RHESSI are normally interpreted in terms of purely collisional electron beam propagation, ignoring spatial evolution and collective effects. In this paper we present self-consistent numerical simulations…
We investigate the signature of the photospheric albedo contribution in solar flare hard X-ray spectra, the effect of low energy cutoffs in electron spectra, and the directivity of hard X-ray emission. Using Ramaty High Energy Solar…
Decades of astrophysical observations have convincingly shown that soft X-ray (SXR; ~0.1--10 keV) emission provides unique diagnostics for the high temperature plasmas observed in solar flares and active regions. SXR observations critical…
Before the onset of a flare is observed in hard X-rays there is often a prolonged pre-flare or pre-heating phase with no detectable hard X-ray emission but pronounced soft X-ray emission suggesting that energy is being released and…