Related papers: Coronal emission lines as thermometers
We present an overview of the physical mechanisms responsible for the coronal polarization at different wavelength regimes. We also review different techniques using coronal polarization to determine various quantities necessary for…
Ordinary metallic photonic crystals (PCs) have photonic band gaps in which the density of states (DOS) is strongly modified. Thermal emission of photons can be suppressed and enhanced accordingly. We consider the thermal emission…
The profiles of emission lines formed in the corona contain information on the dynamics and the heating of the hot plasma. Only recently has data with sufficiently high spectral resolution become available for investigating the details of…
We found 12 unknown visible emission lines from the core plasma of large helical device with highly charged tungsten ions accumulated. The observation was made with our home-built echelle spectrometer, which covers the wavelength range of…
We use a combination of analytical theory, numerical simulation, and data analysis to study the propagation of acoustic waves along coronal loops. We show that the intensity perturbation of a wave depends on a number of factors, including…
We announce a new facility in the spectral code CLOUDY that enables tracking the evolution of a cooling parcel of gas with time. For gas cooling from temperatures relevant to galaxy clusters, earlier calculations estimated the [Fe XIV]…
Coronal loops reveal crucial information about the nature of both coronal magnetic fields and coronal heating. The shape of the corresponding flux tube cross section and how it varies with position are especially important properties. They…
The reconstruction of the differential emission measure (DEM) from observations of spectral line intensities provides information on the temperature distribution of the emission measure in the region observed. The inversion process is known…
The virialization shock around an X-ray cluster primarily heats the ions, since they carry most of the kinetic energy of the infalling gas. Subsequently, the ions share their thermal energy with the electrons through Coulomb collisions. We…
Coronal active regions are observed to get fuzzier and fuzzier (i.e. more and more confused and uniform) in harder and harder energy bands or lines. We explain this evidence as due to the fine multi-temperature structure of coronal loops.…
The perplexing mystery of what maintains the solar coronal temperature at about a million K, while the visible disc of the Sun is only at 5800 K, has been a long standing problem in solar physics. A recent study by Mondal(2020) has provided…
A calorimetric detector for minimally disruptive measurements of atomic hydrogen beams is described. The calorimeter measures heat released by the recombination of hydrogen atoms into molecules on a thin wire. As a demonstration, the…
It has long been observed that the number of weak lines from many-electron atoms follows a power law distribution of intensity. While computer simulations have reproduced this dependence, its origin has not yet been clarified. Here we…
Observations of radio noise storms can act as sensitive probes of nonthermal electrons produced in small acceleration events in the solar corona. We use data from noise storm episodes observed jointly by the Giant Metrewave Radio Telescope…
Characteristic properties of secondary electrons emitted from irradiated two-dimensional materials arise from multi-length and time-scale relaxation processes that connect the initial non-equilibrium excited electron distribution with their…
We conduct the first systematic survey of a comprehensive set of the twenty optical coronal lines in the spectra of nearly 1 million galaxies observed by the Sloan Digital Sky Survey (SDSS) Data Release 8 catalog. This includes often…
In the work described here we investigate atomic processes leading to the formation of emission lines within the IRIS wavelength range at temperatures near $10^5$~K. We focus on (1) non-equilibrium and (2) density-dependent effects…
Context: Long-period intensity pulsations were recently detected in the EUV emission of coronal loops, and have been attributed to cycles of plasma evaporation and condensation driven by thermal non-equilibrium (TNE). Numerical simulations…
The thermodynamic evolution of Coronal Mass Ejections (CMEs) in the inner corona (< 1.5 R$_{sun}$) is not yet completely understood. In this work, we study the evolution of thermodynamic properties of a CME core observed in the inner corona…
We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of…