Context. Imaging spectrographs are popular instruments used to obtain solar data. They record quasi-monochromatic images at selected wavelength positions. By...

Context. The use of instruments that record narrowband images at selected wavelengths is a common approach in solar observations. They allow scanning of a...

Umbral dots (UDs) are transient, bright features observed in the umbral region of a sunspot. We study the physical properties of UDs observed in sunspots of...

Chromospheric umbral oscillations produce periodic brightenings in the core of some spectral lines, known as umbral flashes. They are also accompanied by...

A systematic structuring of magnetic fields over scales much smaller than the mean free path of photospheric photons may be responsible for the observed...

One important feature of sunspots is the presence of light bridges. These structures are elongated and bright (as compared to the umbra) features that seem to...

We show that cyclic activity and Maunder-type grand minima can be explained by a dynamo driven by the instability of magnetic flux tubes in the overshoot layer...

The spectroscopic determinations of the solar magnetic fields are based on the Zeeman effect observed in relation to a number of absorption lines of the solar...

Context. Umbral chromospheric observations show the presence of magnetoacoustic shocks. Several recent studies have reported magnetic field fluctuations...