The topic of this thesis are the changes to spectral line profiles observed in varying heights of the solar atmosphere. Gas motions in the atmosphere manifest as Doppler shifts and asymmetries in the line profiles. These changes vary over the solar disk, depending on the conditions of the line...

Formation of Intergranular Lanes and Acoustic Events

The vertical component of the magnetic field B⊥ was determined and evaluated at the boundary between the penumbra and the umbra for 11 fully developed sunspots observed with the GRIS@GREGOR instrument.

Context. Jurcak et al. (submitted to A&A) found no dependence of the vertical magnetic field component <|Bver|>_ψ at the umbral boundary of sunspots on area in their statistical study of 79 active regions, whereby <.>_ψ stands for average along the contour.

Aims. We investigate the temporal...

The aim of this Master research is the investigation of the evolution of the moat flow around sunspots. The behaviour of the flow, which is directed radially away from the spot, while the sunspot decays and the interaction with the surrounding network, i.e. supergranules, are analysed.

All data...

Image reconstruction algorithms are today’s most sophisticated tools astronomers have at hand besides telescopes. They are not only used to decrease artifacts, they are also capable of restoring information hidden in the turbulent motion of Earth’s atmosphere. In this thesis two of these algorithms...

Until today, the origin of the solar 11-year activity cycle, in which sunspots emerge predominantly at times of high surface magnetic field strength, has not been sufficiently explained by physical theory.

State-of-the-art dynamo theory uses several different approaches to describe the phenomenon...