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EP: Fachverband Extraterrestrische Physik
EP 9: Sonne und Heliosphäre II
EP 9.6: Vortrag
Freitag, 1. März 2013, 10:45–11:00, HS 9
Helicity transport in a simulated coronal mass ejection — •Norbert Seehafer1 and Bernhard Kliem1,2 — 1Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, GERMANY — 2Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
It has been suggested that coronal mass ejections (CMEs) remove the magnetic helicity of active regions from the Sun. Such removal is often regarded to be necessary due to the hemispheric sign preference of the helicity, which inhibits a simple annihilation by reconnection between volumes of opposite chirality. We have monitored the relative magnetic helicity contained in the coronal volume of a simulated flux rope CME, as well as the upward flux of helicity through a horizontal plane in the simulation box, both based on exact new expressions for the computation of the relative helicity from the magnetic field in the box. The unstable and erupting flux rope carries away only part of the initial helicity through the open upper boundary; the larger part remains in the volume. We suggest a simple physical explanation for this result and perform a parametric study of the helicity shedding in our CME model.