Related papers: Non-thermal processes in coronae and beyond
Binaries hosting a massive star and a non-accreting pulsar are powerful non-thermal emitters due to the interaction of the pulsar and the stellar wind. The winds of massive stars are thought to be inhomogeneous, which could have an impact…
Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics &…
Observations of the Sun and of Sun-like stars provide access to different aspects of stellar magnetic activity that, when combined, help us piece together a more comprehensive picture than can be achieved from only the solar or the stellar…
We analyzed the occurrence rates of flares on stars of spectral types K, G, F, and A, observed by Kepler. We found that the histogram of occurrence frequencies of stellar flares is systematically shifted towards a high-energy tail for…
We study the emission and absorption spectra due to various photon and pair processes in a non-equilibrium pair plasma containing a significant density of photons. We present here some preliminary results from Monte-Carlo simulations. These…
The relevance of non-thermal cluster studies and the importance of combining observations of future radio surveys with WFXT data are discussed in this paper.
We present preliminary results of grating observations of YY Mensae and V824 Arae by Chandra and XMM-Newton. Spectral features are presented in the context of the emission measure distributions, the coronal abundances, and plasma electron…
Radio observations of cool stellar systems provide unique information on their magnetic fields, high-energy processes, and chemistry. Buoyed by powerful new instruments (e.g. ALMA, JVLA, LOFAR), advances in related fields (e.g., the Gaia…
Nanoflares in quiet-Sun regions during solar cycle 24 are studied with the best available plasma diagnostics to derive their energy distribution and contribution to coronal heating during different levels of solar activity. Extreme…
Temporary enhancements of the coronal emission measure in a quiet region have been shown to constitute a significant energy input. Here some relatively large events are studied for simultaneous brightenings in transition region lines and in…
Recent experimental data and progress in nuclear structure modeling have lead to improved descriptions of astrophysically important weak-interaction processes. The review discusses these advances and their applications to hydrostatic solar…
Observations with {\em RHESSI} have enabled the detailed study of the structure of dense hard X-ray coronal sources in solar flares. The variation of source extent with electron energy has been discussed in the context of streaming of…
Turbulent convection is certainly one of the most important and thorny issues in stellar physics. Our deficient knowledge of this crucial physical process introduces a fairly large uncertainty concerning the internal structure and evolution…
Context: One of the most prominent processes suggested to heat the corona to well above 10^6 K builds on nanoflares, short bursts of energy dissipation. Aims: We compare observations to model predictions to test the validity of the…
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 numerical simulation of turbulence in stars has led to a rich set of possibilities regarding stellar pulsations, asteroseismology, thermonuclear yields, and formation of neutron stars and black holes. The breaking of symmetry by…
We propose a novel component to the understanding of the temperature structure of galaxy clusters which does not rely on any heating or cooling mechanism. The new ingredient is the use of non-extensive thermo-statistics which is based on…
As solar coronal mass ejections (CMEs) propagate through the heliosphere, they expend energy in heating protons to compensate for the cooling that occurs due to expansion. CME propagation models usually treat energy dissipation implicitly…
Determining the mechanisms responsible for the heating of the coronal plasma and maintaining and accelerating the solar wind are long standing goals in solar physics. There is a clear need to constrain the energy, mass and momentum flux…
X-ray emission from cool stars is an important tracer for stellar activity. The X-ray luminosity reflects different levels of activity and covers four orders of magnitude in stars of spectral types M-F. Low spectral resolution provided by…