Bonn 2010 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 3: Poster

EP 3.27: Poster

Montag, 15. März 2010, 17:45–19:00, AKM Foyer

Mesh adaptive numerical simulation of current sheet formation at quasi-separatrix layers — •Kay Thust, Frederic Effenberger, Jürgen Dreher, and Rainer Grauer — Theoretische Physik I, Ruhr-Universität Bochum, Germany

Magnetic reconnection is thought to play a major role in the understanding of the coronal heating problem and the mechanisms leading to solar flares and coronal mass ejections. One preferential site for reconnection are thin current sheets.

To study the formation of current sheets, models without separators or null points are of particular interest. In these models quasi-separatrix layers, which are defined by a strong but still continuous variation of the field line linkage, play a role similar to classical separators.

In a numerical experiment based on ideal MHD, Aulanier et al. (A&A, 2005) studied a magnetic field configuration with a quadrupolar photospheric signature that contains a hyperbolic flux tube. As remarked by those authors, a further analysis of the small-scale structures was limited by the resolution of the numerical mesh.

To alleviate this problem, we have carried out similar MHD simulations using the technique of adaptive mesh refinement (AMR), which allowed us to achieve local resolutions of up to 81923 in the areas of interest, more than a factor of 10 higher than the runs by Aulanier et al. On these scales our results still largely confirm the previous work, which also showed a collapse of the current sheet down to the mesh resolution.

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