Berlin 2014 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 5: Low Temperature Plasmas I
P 5.1: Hauptvortrag
Montag, 17. März 2014, 16:30–17:00, SPA HS201
Guide field effects on magnetic reconnection — •Adrian von Stechow1, Olaf Grulke1, and Thomas Klinger1,2 — 1Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Greifswald — 2Ernst Moritz Arndt-Universität Greifswald
Magnetic reconnection, a topological rearrangement of opposed magnetic fields, is a ubiquitous plasma phenomenon and is suggested to play an important role in, e.g., particle acceleration and heating. The details of the reconnection process depend strongly on the magnetic field configuration. A superimposed guide field has been shown to alter fundamental reconnection parameters due to modifications of the current pattern, by e.g. inhibiting Hall currents and causing a pile-up of magnetic flux at the X-point. Additionally, electromagnetic micro-instabilities are believed to contribute to the fast reconnection process.
The present contribution deals with the detailed experimental study of the current sheet fluctuations under varying guide field conditions. The experiments are conducted in two paradigmatic and complementary laboratory configurations: MRX (PPPL, Princeton) is a closed field line, toroidal device with a weak guide field and a Harris sheet-like reconnection current. In contrast, VINETA II (IPP, Greifswald) is an open field line, linear and moderate to high guide field experiment in which the current sheet is predominantly set by the magnetic field geometry. Despite the different configurations, observed instabilities show similar features such as localization within the current sheet, broadband frequency spectra in the lower hybrid range and extremely short correlation lengths.