Related papers: Kappa distribution and hard X-ray emission of sola…
We compare the soft diffuse X-ray emission from Chandra images of 12 nearby intermediate inclination spiral galaxies to the morphology seen in Halpha, molecular gas, and mid-infrared emission. We find that diffuse X-ray emission is often…
Elemental abundances in the solar corona are known to be different from those observed in the solar photosphere. The ratio of coronal to photospheric abundance shows a dependence on the first ionisation potential (FIP) of the element. We…
We show that the hard X-ray (HXR) emission observed from several galaxy clusters is naturally explained by a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by…
The problem of beam propagation in a plasma with small scale and low intensity inhomogeneities is investigated. It is shown that the electron beam propagates in a plasma as a beam-plasma structure and is a source of Langmuir waves. The…
Energetic particle populations are ubiquitous throughout the Universe. In our solar system, the most prominent sources of energetic particles are solar flares or collisionless shocks often driven by huge eruptions of magnetised plasma…
The Chandra X-ray Observatory grating spectrometers allow study of stellar spectra at resolutions on the order of 1000. Prior x-ray observatories' low resolution data have shown that nearly all classes of stars emit x-rays. Chandra reveals…
The pseudo-potential method is applied to derive diverse propagating electron hole structures, in a nonthermal or $\kappa$ particle distribution function background. The associated distribution function Ansatz reproduces the Schamel…
Solar active regions contain electric currents. Information on the distribution of currents is important for understanding the processes of energy release on the surface of the Sun and in the overlying layers. The paper presents an analysis…
We present results of a study of non-thermal, time-dependent particle injection in a corona around an accreting black hole. We model the spectral energy distribution of high-energy flares in this scenario. We consider particle interactions…
In the classical flare picture, hard X-ray emission from the chromosphere is succeeded by soft-X-ray emission from hot plasma in the flare loop, the soft X-ray emission being a direct consequence of the impact of the non-thermal particle…
The basis for the application of Thomson scattering to the analysis of coronagraph images has been laid decades ago.Even though the basic formulation is undebated, a discussion has grown in recent years about the spatial distribution of…
A long BeppoSAX observation of the Galactic Center region shows that the spectrum of the diffuse X-ray emission from the SgrA Complex can be described with the sum of two thermal plasma models with temperatures of ~0.6 keV and \~8-9 keV.…
Non-thermal particle acceleration in the solar corona is evident from both remote hard X-ray (HXR) sources in the chromosphere and direct in-situ detection in the heliosphere. Correlation of spectral indices between remote and in-situ…
This paper reports on the re-analysis of solar flares in which the hard X-rays (HXRs) come predominantly from the corona rather than from the more usual chromospheric footpoints. All of the 26 previously analyzed event time intervals, over…
We develop the kappa-tail fitting technique, which analyzes observations of power-law tails of distributions and energy-flux spectra and connects them to theoretical modeling of kappa distributions, to determine the thermodynamics of the…
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…
Unsteady activity of gamma-ray burst sources leads to internal shocks in their emergent relativistic wind. We study the emission spectra from such shocks, assuming that they produce a power-law distribution of relativistic electrons and…
We review the presence and signatures of the non-equilibrium processes, both non-Maxwellian distributions and non-equilibrium ionization, in the solar transition region, corona, solar wind, and flares. Basic properties of the non-Maxwellian…
Microwave emission of solar flares is formed primarily by incoherent gyrosynchrotron radiation generated by accelerated electrons in coronal magnetic loops. The resulting emission depends on many factors, including pitch-angle distribution…
The solar corona is full of dynamic phenomena, e.g., solar flares, micro flares in active regions, jets in coronal holes and in the polar regions, X-ray bright points in quiet regions, etc. They are accompanied by interesting physical…