Wuppertal 2015 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 6: Postersitzung
EP 6.1: Poster
Wednesday, March 11, 2015, 16:45–18:45, Foyer Ebene G.10
How to compare coronal magnetic field models and coronal images? — Ioanna-Amaryllis Patsou and •Thomas Wiegelmann — Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077, Göttingen
The coronal magnetic field controls the structure and most physical processes in the solar corona. Up to date accurate measurements of the magnetic field vector are regularly available only in photospheric levels and the 3D coronal magnetic field is mainly modelled by extrapolation of the photospheric magnetic field vector into the corona. One has also to make assumptions for the coronal current density. In the low corona above Active Regions the average plasma beta parameter is about 10−4 to 10−2 and plasma forces can be neglected. Then the Lorentz-force vanishes and the electric currents flow parallel to the magnetic field, leading to ∇ × B =α B. In this work photospheric magnetic field measurements of ARs from SDO/HMI have been extrapolated using potential (α=0), linear force-free (α=constant) and nonlinear force-free (α varies in space) models. A complementary approach to derive coronal magnetic loops (but only in 2D) is through coronal EUV-images, because the highly conductive coronal plasma outlines the magnetic field lines. We have combined high-resolution EUV coronal loop images from SDO/AIA with the 3D reconstructed magnetic field in order to obtain information about the magnetic field topology of coronal loops above ARs. We derived quantitative criteria to compare magnetic loops visible in AIA-images with field lines from 3D coronal magnetic field models.