Stuttgart 2012 – wissenschaftliches Programm
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SYGP: Symposium Gemeinsame Probleme in Fusions- und astrophysikalischen Plasmen
SYGP 3: Contributed Talks
SYGP 3.6: Vortrag
Montag, 12. März 2012, 17:45–18:00, V55.22
Gyrokinetic simulations of magnetic reconnection — •Daniel Told1, Moritz Johannes Pueschel1,2, Frank Jenko1, and Jörg Büchner2 — 1Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching, Germany — 2Max-Planck-Institut für Sonnensystemforschung, D-37191 Katlenburg-Lindau, Germany
Fast magnetic reconnection, believed to be a mechanism for rearranging the magnetic topology and creating energetic particles in many astrophysical and laboratory plasmas, is investigated with the nonlinear gyrokinetic code GENE. After some code-code benchmarking, extensive linear studies are presented, covering all relevant parameter dependencies of two-dimensional slab reconnection. The results are shown to agree well with a standard fluid model, if its assumptions are strictly fulfilled. In many realistic applications, however, the results deviate substantially, stressing the need for a generalized model or numerical simulations.
Nonlinear simulations are performed for two scenarios: decaying and driven turbulence. In the former case, the initially injected energy cascades towards the largest scales of the system and forms isotropic field structures after the transient turbulent phase. On the other hand, if the system is driven through a Krook-type term in the gyrokinetic Vlasov equation, a fully turbulent, quasi-stationary state develops. In this case, structures and islands are formed whose properties depend significantly on the drive strength. In both cases, the creation of significant parallel electric fields, largely due to magnetic flutter, is observed.