HR: 10:35h
AN: SM52A-02    [Abstracts]
TI: Cluster Observations of Alfvenic Vortices in the Magnetosheath
AU: Olga, A
EM: olga.alexandrova@obspm.fr
AU: * Andre, M
EM: mangeney@despace.obspm.fr
AU: Milan, M
EM: milan.maksimovic@obspm.fr
AF: Observatoire de Paris, Place Janssen, Meudon, 92195 France
AB: Recent observations by the CLUSTER spacecraft (O. Alexandrova et al, 2005) have revealed the presence of localized magnetic current tubes in the magnetosheath behind quasiperpendicular bowshocks. These structures appear in the spectrum of magnetic fluctuations as a peak located at a frequency, of the order of the proton or alpha particle gyrofrequency, separating a low frequency relatively flat spectrum and a high frequency, much steeper spectrumi (see Czaykowwska et al, 2001). They are shown to be Alfvenic vortices with axis closely aligned with the ambiant magnetic field and almost stationary in the magnetosheath plasma. We discuss the generation of these vortices, and their possible role in the magnetosheath turbulence.
DE: 2149 MHD waves and turbulence (2752, 6050, 7836)
DE: 2728 Magnetosheath
DE: 7836 MHD waves and instabilities (2149, 2752, 6050)
DE: 7839 Nonlinear phenomena (4400, 6944)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005