The three-dimensional topology of magnetic fields in and around sunspots

Abstract

The most prominent features on the surface of the solar disc are the sunspots, which have been studied since their detection in the 17th century. Despite this years and centuries of scientific investigations, surprisingly many facets of sunspots are not well understood. In this thesis, the properties of a sunspots' penumbra are derived from the observed spectra by means of an inversion, a forward modeling technique. A method for the construction of a 3-dimensional model of the field topology from the inversion results is presented. It offers the possibility to build a toy-model of the spot. This allows to investigate the relationships between the geometry and other properties of the sunspot like flow velocities, intensity, temperature, or field strength. The application of the procedure to time series of observations will allow to study the temporal evolution of the geometry and the other properties, to determine the physical processes happening and their respective drivers. A second part of the thesis is devoted to the analysis of isolated field concentrations in the surroundings of the sunspot. These isolated magnetic elements are assumed to be the elementary building blocks of the solar surface magnetism. In the turbulent surroundings of the solar atmosphere, only relatively strong concentrations with a field strength above 1 kG are assumed to be stable at all ...