Spektroskopie und Polarimetrie kleinskaliger magnetischer Strukturen der Sonnenoberfläche mit Methoden der Bildrekonstruktion

Abstract

Speckle observations of small-scale magnetic structures on the Sun are presented. They were obtained with the Göttingen Fabry-Perot interferometer (FPI) in the Vacuum Tower Telescope at the Observatorio del Teide, Tenerife, from quiet and active regions close to disc center. A Stokes-V-polarimeter was added to the FPI to measure V-profiles in the FeI line at 630.25 nanometer. The setup allows image reconstruction with speckle methods, phase diversity and other methods. The achieved spatial resolution in the magnetograms is 0.4 - 0.5 arcseconds. The observational technique and the data reduction are described in detail. The results from small-scale magnetic flux elements in a very quiet region, in an active region, and in a sunspot with its surroundings are discussed.In the quiet Sun, granular dynamics dominate the time evolution of the magnetic elements. Flux occurs in both bright intergranular points and in dark intergranular spaces. Likewise, with the present spatial resolution, no preference of magnetic flux in abnormal granulation in an active region can be found. Flux occurs in both bright (abnormal) small-scale granules and in the darker spaces in between them. The small sunspot studied has very little magnetic flux in its ambient quiet regions, especially no strong, conspicuous concentrations of returned flux, i.e. of flux with the opposite polarity.