Bochum 2015 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 5: Poster Session - Low Temperature Plasmas
P 5.4: Poster
Montag, 2. März 2015, 16:30–18:30, Foyer Audimax
Current sheet dynamics during driven magnetic reconnection — •Adrian von Stechow1, Olaf Grulke1, and Thomas Klinger1,2 — 1Max-Planck-Institut für Plasmaphysik, Greifswald — 2Ernst Moritz Arndt-Universität Greifswald
Magnetic reconnection is a ubiquitous plasma phenomenon which enables the release of accumulated magnetic energy by rapid changes in magnetic topology, thereby generating fast particles and allowing a wealth of instabilities to grow. A central feature is the formation of a localized current sheet along the X-line between opposed magnetic fields, of which the plasma parameters, boundary conditions and instabilities determine the rate at which reconnection proceeds. These quantities are characterized for two paradigmatic and complementary laboratory configurations: MRX (PPPL, Princeton) is a closed field line, toroidal device with a weak guide field. In contrast, VINETA II (IPP, Greifswald) is an open field line, linear and moderate to high guide field experiment. At comparable plasma parameters, similar features are observed in the microscopic fluctuations within both experiments, such as localization of the fluctuations within the current sheet, broadband frequency spectra with a spectral kink near the lower hybrid frequency and short correlation lengths. The current sheet parameters in both experiments are favorable for growth of the electrostatic lower hybrid mode, while magnetic dispersion measurements show whistler-like wave propagation along the magnetic field. These fluctuations are found to be intrinsic to the localized current sheet and are independent of the slower reconnection dynamics.