Stuttgart 2012 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 7: Poster Erdnaher Weltraum
EP 7.5: Poster
Mittwoch, 14. März 2012, 16:30–19:00, Poster.IV
Linearized MHD simulation of a double gradient magnetic instability — •Daniil B. Korovinskiy1, Andrey V. Divin2, Nikolay V. Erkaev3, Viktoria V. Ivanova4, Ivan B. Ivanov5, Vladimir S. Semenov6, and Helfried K. Biernat1 — 1Space Research Institute, Austrian Academy of Sciences, 8042, Graz, Austria — 2Centrum voor Plasma-astrofysica, Departement Wiskunde, Katholieke Universiteit Leuven, B-3001, Belgium — 3Institute of Computational Modeling, Russian Academy of Sciences, Siberian Branch, 660036, Krasnoyarsk, Russia — 4Orel State Technical University, 302020, Orel, Russia — 5Theoretical Physics Division, Petersburg Nuclear Physics Institute, 188300, Gatchina, Russia — 6Saint Petersburg State University, 198504, Petrodvoretz, Russia
The double gradient mode, which is believed to be responsible for magnetotail flapping oscillations, is studied. Linearized MHD simulations of the unstable kink branch are performed using the two-dimensional magnetotail-like equilibrium.
The results are in agreement with the theory, and the growth rates are close to the peak values, provided by the analytical estimates. It is found that the simulation results better match the analytical predictions, if the background state satisfies the force balance with a good accuracy.
The instability development is investigated for a set of values of the normal component gradient. In accordance with the analytical theory, the typical growth rate values depend linearly on the square root of the gradient.