The acceleration of the low-latitude solar wind, which comes from regions of the corona above large, closed magnetic loops, is a theoretical challenge. Until recently we have lacked direct measurements close to the Sun with which to constrain the theory. When a series of high-resolution coronagraph images is viewed in the form of a movie the continuous outflow of matter from the Sun is very obv...

The most fundamental problem in solar system research is still unsolved: how can the Sun with a surface temperature of only 5800 K heat up its atmosphere to more than a million K? In fact, the solar atmosphere is so hot that not even the Sun’s enormous gravity can contain it. Part of it is continuously evaporating into interplanetary space: the SOLAR WIND. As a highly ionized magnetized plasma ...

We have investigated the effects of resonant scattering of emission lines on the image morphology and intensity from coronal loop structures. It has previously been shown that line of sight effects in optically thin line emission can yield loop images that appear uniformly bright at one viewing angle, but show “looptop sources” at other viewing angles. For optically thick loops where multiple r...

The radio signature of a shock travelling through the solar corona is known as a type II solar radio burst. In rare cases these bursts can exhibit a fine structure known as “herringbones”, which are a direct indicator of particle acceleration occurring at the shock front. However, few studies have been performed on herringbones and the details of the underlying particle acceleration processes a...

In this paper, we present a detailed study of a two-ribbon flare in the plage region observed by Kanzelhohe Solar Observatory (KSO), which is one of the stations in our global H network. We select this event due to its very clear filament eruption, two-ribbon separation, and association with a fast coronal mass ejection (CME). We study the separation between the two ribbons seen in H as a funct...

The plasma contributing to emission from the Sun between cool chromosphere ($\le 10^4$K) and hot corona ($\ge 10^6$K) has been subjected many different interpretations. Here we look at magnetic structure of this transition region (TR) plasma, based upon implications CLASP2 data an active recently published by Ishikawa et al., earlier IRIS SDO quiet regions. al. found that large areas sunspot pl...

Recent simulations of solar active regions have shown that it is possible to reproduce both the total intensity and the general morphology of the high temperature emission observed at soft X-ray wavelengths using static heating models. There is ample observational evidence, however, that the solar corona is highly variable, indicating a significant role for dynamical processes in coronal heatin...

The formation of extremely hot outer atmospheres is one the most prominent manifestations magnetic activity common to late-type dwarf stars, including Sun. It widely believed that these atmospheric layers, corona, transition region, and chromosphere, are heated by dissipation energy transported upwards from stellar surface field. This signified spectral line fluxes at various wavelengths, scale...

Abstract The magnetic processes associated with the nonthermal broadening of optically thin emission lines appear to carry enough energy heat corona and accelerate solar wind. We investigate whether motions in cool stars exhibit same behavior as on Sun by analyzing archival stellar spectra taken Hubble Space Telescope, full-disk Solar Interface Region Imaging Spectrograph. determined velocities...

Infrared emission lines are potentially sensitive probes of components of the coronal vector magnetic Ðeld, through the Zeeman e†ect, and on its direction projected onto the plane of the sky, through Ñuorescent polarization of scattered photospheric light. Prompted by the advent of sensitive infrared array detectors, existing atomic data were reexamined to compile a complete list of coronal lin...