Related papers: An observationally-driven kinetic approach to coro…
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…
The magnetic fields in the solar atmosphere structure the plasma, store free magnetic energy and produce a wide variety of active solar phenomena, like flare and coronal mass ejections(CMEs). The distribution and strength of magnetic fields…
A hot corona is suggested to be above the standard thin disk. The anisotropy of hard X-ray emission in radio-quiet active galactic nuclei implies that the corona is not static and probably moves outwards like winds. We perform…
The energy input into the lower solar corona by flare evaporation events has been modeled according to the available observations for quiet regions. The question is addressed whether such heating events can provide the observed average…
Cool stars like our Sun are surrounded by a million degree hot outer atmosphere, the corona. Since more than 60 years the physical nature of the processes heating the corona to temperatures well in excess of those on the stellar surface…
The solar atmosphere may be heated by Alfven waves that propagate up from the convection zone and dissipate their energy in the chromosphere and corona. To further test this theory, we consider wave heating in an active region observed on…
The heating of the solar chromosphere and corona to the observed high temperatures, imply the presence of ongoing heating that balances the strong radiative and thermal conduction losses expected in the solar atmosphere. It has been…
The content of coronal material in the quiet Sun is not constant as soft X-ray and high-temperature EUV line observations have shown. New material, probably heated and evaporated from the chromosphere is occasionally injected even in the…
We present the first model that couples the formation of the corona of a solar active region to a model of the emergence of a sunspot pair. This allows us to study when, where, and why active region loops form, and how they evolve. We use a…
The outer solar atmosphere, the corona, contains plasma at temperatures of more than a million K, more than 100 times hotter that solar surface. How this gas is heated is a fundamental question tightly interwoven with the structure of the…
Many studies of the solar corona have shown that the observed X-ray luminosity is well correlated with the total unsigned magnetic flux. In this paper we present results from the extensive numerical modeling of active regions observed with…
We highlight ten key aspects of coronal heating that must be understood before we can consider the problem to be solved. (1) All coronal heating is impulsive. (2) The details of coronal heating matter. (3) The corona is filled with…
Magnetic energy is required to heat the corona, the outer atmosphere of the Sun, to millions of degrees. We study the nature of the magnetic energy source that is probably responsible for the brightening of coronal loops driven by…
The corona of the Sun is dominated by emission from loop-like structures. When observed in X-ray or extreme ultraviolet emission, these million K hot coronal loops show a more or less constant cross section. In this study we show how the…
In a recent computational campaign [Ng et al., Astrophys. J. 747, 109, 2012] to investigate a three-dimensional model of coronal heating using reduced magnetohydrodynamics (RMHD), we have obtained scaling results of heating rate versus…
The opening-up of the magnetic field during solar eruptive events is often accompanied by a dimming of the local coronal emission. From observations of filament eruptions recorded with the Extreme-Ultraviolet Imager on STEREO during…
This paper reviews the current state of our understanding of high-speed solar wind acceleration in coronal holes. Observations by SOHO, coupled with interplanetary particle measurements going back several decades, have put strong…
How the solar atmosphere is heated from a temperature of about $5,000-6,000$\,K in the lower atmosphere to about $1-2$\,MK in the corona has challenged the astrophysical community for about 80 years. The same puzzle exists for the stellar…
This Letter reports the first observational estimate of the heating rate in the slowly expanding solar corona. The analysis exploits the simultaneous remote and local observations of the same coronal plasma volume with the Solar…
Advanced 3D radiative MHD simulations now reproduce many properties of the outer solar atmosphere. When including a domain from the convection zone into the corona, a hot chromosphere and corona are self-consistently maintained. Here we…