Related papers: Chromospheric Dynamics and Line Formation
Waves are an integral part of the solar atmosphere, and their characteristics (e.g., dominant period, range of periods, power, and phase angle) change on a diverse spatio-temporal scale. It is well well-established observationally that the…
For many years various asymmetrical profiles of different spectral lines emitted from solar flares have been frequently observed. These asymmetries or line shifts are caused predominantly by vertical mass motions in flaring layers and they…
Context. The radiative losses in the solar chromosphere vary from 4~kW~m$^{-2}$ in the quiet Sun, to 20~kW~m$^{-2}$ in active regions. The mechanisms that transport non-thermal energy to and deposit it in the chromosphere are still not…
The solar spectrum conveys most of our diagnostics to find out how our star works. They must be understood for utilization, but solar spectrum formation is complex because the interaction of matter and radiation within the solar atmosphere…
Non-local thermodynamic equilibrium (NLTE) effects in diagnostically important solar Fe I lines are important due to the strong sensitivity of Fe I to ionizing UV radiation, which may lead to a considerable under-population of the Fe I…
Rotation is a significant characteristic of the Sun and other stars, and it plays an important role in understanding their dynamo actions and magnetic activities. In this study, the rotation of the solar chromospheric activity is…
During solar flares, spectral lines formed in the photosphere have been shown to exhibit changes to their profiles despite the challenges of energy transfer to these depths. Recent work has shown that deep-forming spectral lines are subject…
We present significant improvements of our approach in constructing detailed atmospheric models and synthetic spectra for hot luminous stars: 1. A sophisticated and consistent description of line blocking and blanketing. Our solution…
The solar chromosphere is a vigorously dynamic region of the sun, where waves and magnetic fields play an important role. To improve chromospheric diagnostics, we present new observations in Ca II 8542 carried out with the SST/CRISP on La…
Recent experiments on femtosecond pulses in water displayed long distance propagation analogous to that reported in air. We verify this phenomena numerically and show that the propagation is dynamic as opposed to self-guided. Furthermore,…
Waves are observed at all layers of the solar atmosphere and the magnetic field plays a key role in their propagation. While deep down in the atmosphere the p-modes are almost entirely of acoustic nature, in the upper layers magnetic forces…
The very nature of the solar chromosphere, its structuring and dynamics, remains far from being properly understood, in spite of intensive research. Here we point out the potential of chromospheric observations at millimeter wavelengths to…
In this paper, we present a numerical simulation of an impulsively driven chromospheric jet in the solar atmosphere using the non-ideal magnetohydrodynamic (MHD) equations coupled with frequency- and angle-averaged radiation transport…
We solve a hydrodynamic model of active chromatin dynamics, within a confined geometry simulating the cell nucleus. Using both analytical and numerical methods, we describe the behavior of the chromatin polymer driven by the activity of…
The solar atmosphere is permeated by various types of waves that originate from subsurface convection. As these waves propagate upward, they encounter they encounter a steep decrease in the density of the medium, leading to their steepening…
Context. The He i 1083 nm is a powerful diagnostic for inferring properties of the upper solar chromosphere, in particular for the magnetic field. The basic formation of the line in one-dimensional models is well understood, but the…
The origin of the near-ultraviolet and optical continuum radiation in flares is critical for understanding particle acceleration and impulsive heating in stellar atmospheres. Radiative-hydrodynamic simulations in 1D have shown that high…
We study line driven stellar winds using time-dependent radiation hydrodynamics where the continuum radiation couples to the gas via either a scattering or absorption opacity and there is an additional radiation force due to spectral lines…
We have performed 3D radiation MHD simulations extending from the convection zone to the corona covering a box 16 Mm$^3$ at 32 km spatial resolution. The simulations show very fine structure in the chromosphere with acoustic shocks…
Waves and shocks traveling through the solar chromospheric plasma are influenced by its partial ionization and weak collisional coupling, and may become susceptible to multi-fluid effects, similar to interstellar shock waves. In this study,…