Related papers: Structure and Dynamics of Sunspots
We report on new spectro-polarimetric measurements with simultaneous filter imaging observation, revealing the frequent appearance of polarization signals indicating high-speed, probably supersonic, downflows that are associated with at…
High resolution spectropolarimetric observations of 3 sunspots taken with Hinode demonstrate the existence of supersonic downflows at or close to the umbra-penumbra boundary which have not been reported before. These downflows are confined…
In his famous monographs, Einar Tandberg-Hanssen writes that "the single, physically most important parameter to study in prominences may be the magnetic field. Shapes, motions, and in fact the very existence of prominences depend on the…
Various theoretical and observational results have been reported regarding the presence/absence of net electric currents in the sunspots. The limited spatial resolution of the earlier observations perhaps obscured the conclusions. We have…
Solar prominences, or solar filaments, are cool and dense plasma structures in the hot solar corona, whose formation mechanisms have remained a fundamental challenge in solar physics. This review provides a comprehensive overview of the…
Some models for the topology of the magnetic field in sunspot penumbrae predict the existence of field-free or dynamically weak-field regions in the deep Photosphere. To confirm or rule out the existence of weak-field regions in the deepest…
Magnetic bright points are small-scale magnetic elements ubiquitous across the solar disk, with the prevailing theory suggesting that they form due to the process of convective collapse. Employing a unique full Stokes spectropolarimetric…
Context: In sunspots, the geometric height of continuum optical depth unity is depressed compared to the quiet Sun. This so-called Wilson depression is caused by the Lorentz force of the strong magnetic field inside the spots. However, it…
Magnetic fields are essential ingredients of many physical processes in the interiors and envelopes of cool stars. Yet their direct detection and characterisation is notoriously difficult, requiring high-quality observations and advanced…
Solar filaments are an intriguing phenomenon, like cool clouds suspended in the hot corona. Similar structures exist in the intergalactic medium as well. Despite being a long-studied topic, solar filaments have continually attracted…
Whereas penumbral models during the last 15 years have been successful in explaining Evershed flows and magnetic field inclination variations in terms of flux tubes, the lack of contact between these models and a convective process needed…
As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism…
Observations of cool stars reveal dark spot-like features on their surfaces. Compared to sunspots, starspots can be bigger or cover a larger fraction of the stellar surface. While sunspots appear only at low latitudes, starspots are also…
The review addresses the spatial frequency morphology of sources of sunspot oscillations and waves, including their localization, size, oscillation periods, height localization with the mechanism of cut-off frequency that forms the observed…
Solar pores are active regions with large magnetic field strengths and apparent simple magnetic configurations. Their properties resemble the ones found for the sunspot umbra although pores do not show penumbra. Therefore, solar pores…
We employ high-spatial resolution spectropolarimetric observations from the Solar Optical Telescope on-board the Hinode spacecraft to investigate the fine structure of the penumbral magnetic fields. The Stokes vector of two neutral iron…
The torsional oscillation is a well established observational fact and there are theoretical attempts for its description but no final solution has yet been accepted. One of the possible candidates for its cause is the presence of sunspots…
The formation of long-lasting structures at the surfaces of stars is commonly ascribed to the action of strong magnetic fields. This paradigm is supported by observations of evolving cool spots in the Sun and active late-type stars, and…
Magnetic fields emerging from the Sun's interior carry information about physical processes of magnetic field generation and transport in the convection zone. Soon after appearance on the solar surface the magnetic flux gets concentrated in…
Over the last two decades the uninterrupted, high-resolution observations of the Sun, from the excellent range of telescopes aboard many spacecraft complemented with observations from sophisticated ground-based telescopes have opened up a…