Related papers: Coronal Polarization
Coronal hole boundaries are the interfaces between closed and open magnetic field regions in the solar atmosphere. Many fundamental processes take place at these regions, including magnetic reconnection that is responsible for solar wind…
The solar corona, the tenuous outer atmosphere of the Sun, is orders of magnitude hotter than the solar surface. This 'coronal heating problem' requires the identification of a heat source to balance losses due to thermal conduction,…
Polar coronal plumes seen during solar eclipses can now be studied with space-borne telescopes and spectrometers. We briefly discuss such observations from space with a view to understanding their plasma characteristics. Using these…
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 question why the solar corona is much hotter than the visible solar surface still puzzles solar researchers. Most theories of the coronal heating involve a tight coupling between the coronal magnetic field and the associated thermal…
Coronae express different facets of their energy release processes in different wavelength regions. While soft X-ray and EUV emission dominates the radiative losses of the thermal plasma, hard X-ray emission (>10 keV) can be produced from…
Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed…
The solar atmosphere being magnetic in nature, the understanding of the structure and evolution of the magnetic field in different regions of the solar atmosphere has been an important task over the past decades. This task has been made…
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…
Due to the continuous developments in polarimetric instrumentation, which will become even more dramatic in the near future with the availability of new generation solar telescopes, we are now severely confronted with a variety of new…
The solar corona has been revealed in the past decade to be a highly dynamic nonequilibrium plasma environment. Both the loop-filled coronal base and the extended acceleration region of the solar wind appear to be strongly turbulent, but…
The heating of magnetized plasma by propagation of Alfven waves is calculated as a function of the magnetic field spectral density. The results can be applied to evaluate the heating power of the solar corona at known data from satellites'…
It is argued that depolarization of solar radio bursts requires reflection off boundary layers no thicker than about a wavelength (a few meters at most) between regions with large density ratios. The implied inhomogeneities suggest that the…
In order to study the solar corona during eclipses, a new telescope was constructed. Three coronal images were obtained simultaneously from one objective of the telescope as the coronal radiation passed through three polarisers (whose…
Solar variability investigations that include magnetic energy coupling are paramount to solving many key solar/stellar physics problems, particularly for understanding the temporal variability of magnetic energy redistribution and heating…
Data obtained in the framework of the INTERBALL-Tail Probe (1995-2000) and RHESSI (from 2002 to the present) projects have revealed variations in the X-ray intensity of the solar corona in the photon energy range of 2-15 keV during the…
With polarization of the cosmic microwave background (CMB) now detected, and confirmed by several independent experiments, the next goal is to characterise accurately its statistical properties. In these lecture notes we review the physical…
Multi-filter images from the solar corona are used to obtain temperature maps which are analyzed using techniques based on proper orthogonal decomposition (POD) in order to extract dynamical and structural information at various scales.…
Strong magnetic fields are of vital importance to the physics of the solar corona. They easily move a rarefied coronal plasma. Physical origin of the main structural element of the corona, the so-called coronal streamers, is discussed. It…
The coronal magnetic field is the prime driver behind many as-yet unsolved mysteries: solar eruptions, coronal heating, and the solar wind, to name a few. It is, however, still poorly observed and understood. We highlight key questions…