Related papers: Inferring the Coronal Density Irregularity from EU…
The spatial variation of physical quantities, such as the mass density, across solar atmospheric waveguides governs the timescales and spatial scales for wave damping and energy dissipation. The direct measurement of the spatial…
The X-ray and extreme-ultraviolet (EUV) emissions from the low-mass stars significantly affect the evolution of the planetary atmosphere. However, it is, observationally difficult to constrain the stellar high-energy emission because of the…
Multi-wavelength solar images in the EUV are routinely used for analysing solar features such as coronal holes, filaments, and flares. However, images taken in different bands often look remarkably similar as each band receives…
Despite decades of studying the Sun, the coronal heating problem remains unsolved. One fundamental issue is that we do not know the spatial scale of the coronal heating mechanism. At a spatial resolution of 1000 km or more it is likely that…
We investigate the standing kink modes of a cylindrical model of coronal loops. The density is stratified along the loop axis and changes discontinuously at the surface of the cylinder. The periods and mode profiles are studies with their…
Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington…
A technique is described for measuring electrical currents in the solar corona. It uses radioastronomical polarization measurements of a spatially-extended radio source viewed through the corona. The observations yield the difference in the…
The amplitude of density turbulence in the extended solar corona, especially near the dissipation scale, impinges on several problems of current interest. Radio sources observed through the turbulent solar wind are broadened due to…
Context. The details of the spectral profiles of extreme UV emission lines from solar active regions contain key information to investigate the structure, dynamics, and energetics of the solar upper atmosphere. Aims. We characterize the…
Two major issues in the specification of the thermospheric density are the definition of proper solar inputs and the empirical modeling of thermosphere response to solar and to geomagnetic forcings. This specification is crucial for the…
An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. As…
Coronal holes (CH) are regions of open magnetic field lines in the solar corona and the source of fast solar wind. Understanding the evolution of coronal holes is critical for solar magnetism as well as for accurate space weather forecasts.…
New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer sub-structures within coronal loop cross sections, in order to…
Two of the most attractive spectral windows for spectropolarimetric investigations of the physical properties of the plasma structures in the solar chromosphere and corona are the ones provided by the spectral lines of the He I 10830 A and…
We identify coronal holes using a histogram-based intensity thresholding technique and compare their properties to fast solar wind streams at three different points in the heliosphere. The thresholding technique was tested on EUV and X-ray…
Previous solar observations have shown that coronal loops near 1 MK are difficult to reconcile with simple heating models. These loops have lifetimes that are long relative to a radiative cooling time, suggesting quasi-steady heating. The…
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 grating instruments on board Chandra and XMM-Newton now allow measurements of electron densities. These rely on the ratios of fluxes in emission lines, where one line depends on both collisional and radiative decay rates. The electron…
We present first results of a novel technique that provides, for the first time, constraints on the energy input flux at the coronal base ($r\sim\,1.025\,{\rm R}_\odot$) of the quiet-Sun at a global scale. By combining differential emission…
We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the DEM measurements using EUV observations. We derived line of sight component of the coronal…