HR: 0800h
AN: SM51A-1277    [Abstracts]
TI: Anisotropic Spatial Turbulent Spectra in the Magnetosheath: Cluster Results
AU: * Sahraoui, F
EM: fouad.sahraoui@cetp.ipsl.fr
AF: CETP/CNRS-UVSQ, 10/12, av. de l'Europe, V‚lizy, 78140 France
AU: Belmont, G
EM: gerard.belmont@cetp.ipsl.fr
AF: CETP/CNRS-UVSQ, 10/12, av. de l'Europe, V‚lizy, 78140 France
AU: Rezeau, L
EM: laurence.rezeau@cetp.ipsl.fr
AF: CETP/CNRS-UVSQ, 10/12, av. de l'Europe, V‚lizy, 78140 France
AU: Pin‡on, J
EM: jlp@cnrs-orleans.fr
AF: LPCE/CNRS, 3A, av. de la Recherche Scientifique, Orl‚ans, 45071 France
AU: Cornilleau-Wehrlin, N
EM: nicole.cornilleau@cetp.ipsl.fr
AF: CETP/CNRS-UVSQ, 10/12, av. de l'Europe, V‚lizy, 78140 France
AU: Balogh, A
EM: a.balogh@ic.ac.uk
AF: Imperial College, Prince Consort road, London, SW7 2AZ United Kingdom
AB: Mirror modes are known to develop in high beta plasmas when the ion perpendicular temperature is larger than the parallel one. Such physical conditions are usually met in the in front of magnetized planets, due to the solar wind compression in these regions. In the terrestrial magnetosheath, Sahraoui et al (2003, 2004) have shown in a case study that most of the magnetic fluctuations observed in the frequency range [0-5fci] belong unambiguously to this mode, by making use of the CLUSTER data, analyzing them through the so-called k-filtering technique, and comparing them with the theoretical kinetic linear prediction. Here, we present an extension of these previous analyses by providing the first complete 3D k spectra of the observed turbulence. A strong anisotropy is observed in the turbulence, which is shown to be controlled by both the static magnetic field and the magnetopause normal. This leads to a quasi-1D cascade, with a new power law, determined over more than one decade, which characterizes this incoherent mirror turbulence. We will also emphasize the experimental constraints that are due to the Cluster separations for such turbulence studies, and the need of a new theory of magnetized compressible turbulence to interpret these new observations.
DE: 2728 Magnetosheath
DE: 2772 Plasma waves and instabilities (2471)
DE: 7835 Magnetic reconnection (2723, 7526)
DE: 7836 MHD waves and instabilities (2149, 2752, 6050)
DE: 7863 Turbulence (4490)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005