Würzburg 2018 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 3: Sun and Heliosphere I - Structure (MHD, Corona, TR, SW-acc.-Region)
EP 3.1: Hauptvortrag
Dienstag, 20. März 2018, 16:30–17:00, BSZ - Pabel HS
Helicity in the solar atmosphere — •Gherardo Valori1 and Etienne Pariat2 — 1University College London - Mullard Space Science Laboratory - Holmbury St. Mary - Dorking - Surrey - RH5 6NT — 2Observatoire de Paris-Meudon LESIA Batiment 14 5 Place J. Jansen 92195 Meudon France
Magnetic helicity is a geometrical measure of the entanglement of magnetic field lines that is approximately conserved by the magneto-hydrodynamical equations even in the presence of reconnection. It has therefore been proposed as the conceptual tool to understand highly nonlinear dynamical processes in plasmas, like the re-arrangement of post-disruption magnetic fields in tokamaks or the occurrence of coronal mass ejections. However, given its global character and stringent mathematical formulation, magnetic helicity is of difficult application to natural systems as they occur, for instance, in the solar atmosphere. This talk will report on a series of tests on the reliability of magnetic helicity computations, and address the conservations properties of helicity and its link to the stability of coronal structures that are important in modeling coronal mass ejections.