Shear driven waves in the induced magnetosphere of Mars

H. Gunell (1) , U. V. Amerstorfer (2, 3) , Hans Nilsson (4) , Cyril Grima (5) , M. Koepke (1) , M. Franz (6) , J. Winningham (7) , R. A. Frahm (7) , J.-A. Sauvaud (8) , A. Fedorov (8) , N. V. Erkaev (9) , H. K. Biernat (2, 3) , M. Holmström (4) , R. Lundin (4) , S. Barabash (4)

1 Department of Physics [Morgantown}
2 IWF - Space Research Institute of Austrian Academy of Sciences
3 Institute of Physics
4 IRF - Swedish Institute of Space Physics [Uppsala]
5 LPG - Laboratoire de Planétologie de Grenoble
6 MPS - Max-Planck-Institut für Sonnensystemforschung
7 Space Science and Engineering Division [San Antonio]
8 CESR - Centre d'étude spatiale des rayonnements
9 Institute of Computational Modelling

We present measurements of oscillations in the electron density, ion density and ion velocity in the induced magnetosphere of Mars. The fundamental frequency of the oscillations is a few millihertz, but higher harmonics are present in the spectrum. The oscillations are observed in a region where there is a velocity shear in the plasma flow. The fundamental frequency is in agreement with computational results from an ideal-MHD model. An interpretation based on velocity-shear instabilities is described.

Keywords: SOLAR-WIND INTERACTION; KELVIN-HELMHOLTZ INSTABILITY; MARTIAN ATMOSPHERE; VELOCITY SHEAR; VENUS; PLASMA; MHD; IONOPAUSE; SIMULATIONS; BOUNDARY

H. Gunell, U. V. Amerstorfer, Hans Nilsson, Cyril Grima, M. Koepke, et al.. Shear driven waves in the induced magnetosphere of Mars. Plasma Physics and Controlled Fusion, 2008, 50 (7), pp.074018. ⟨10.1088/0741-3335/50/7/074018⟩. ⟨insu-00360495⟩