Kiel 2011 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 10: Poster: Astro- und geophysikalische Plasmen, warme dichte Plasmen

P 10.4: Poster

Dienstag, 29. März 2011, 17:00–19:00, Foyer

Dispersion of magnetoacoustic waves in the anisotropic magnetosheaths of Earth, Jupiter, and Saturn — •Christoph Maurer, Claudia-Veronika Meister, and Dieter Heinz Hermann Hoffmann — Institut für Kernphysik, TU Darmstadt, Schlossgartenstraße 9, 64289 Darmstadt, Germany

In the magnetosheath plasmas of Earth, Jupiter and Saturn anisotropies of the plasma parameters are caused by strong magnetic fields via Lorentz forces. These anisotropies influence the dispersion relation of excited magnetohydrodynamic waves considerably. In the present work, based on the double-adiabatic Chew-Goldberger-Low approximation, the dispersion of magnetoacoustic waves and the variations of the polytropic coefficient of the plasma by these waves are studied. It is shown that in the case of slow magnetoacoustic waves, regions with effective polytropic coefficients smaller than unity may exist in the magnetosheaths of the three studied planets. Additionally, growth rates of the magnetoacoustic waves are estimated using kinetic theory.