HR: 1340h
AN: SM13B-1212    [Abstracts]
TI: Rolled-up Kelvin-Helmholtz vortices at the flank magnetopause and their implications for the formation of the low-latitude boundary layer
AU: * Hasegawa, H
EM: hiroshi.hasegawa@dartmouth.edu
AF: Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755 United States
AU: Fujimoto, M
EM: fujimoto@geo.titech.ac.jp
AF: Tokyo Institute of Technology, Meguro, Tokyo, 152-8551 Japan
AU: Phan, T D
EM: phan@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720-7540 United States
AU: Reme, H
EM: Henri.Reme@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, BP-4346, Toulouse, 31029 France
AU: Balogh, A
EM: a.balogh@imperial.ac.uk
AF: Imperial College, London, London, SW7 2BZ United Kingdom
AU: Dunlop, M W
EM: M.W.Dunlop@rl.ac.uk
AF: Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX United Kingdom
AU: Hashimoto, C
EM: hashimoto@geo.titech.ac.jp
AF: Tokyo Institute of Technology, Meguro, Tokyo, 152-8551 Japan
AU: TanDokoro, R
EM: rtdokoro@geo.titech.ac.jp
AF: Tokyo Institute of Technology, Meguro, Tokyo, 152-8551 Japan
AB: We report unambiguous evidence for rolled-up Kelvin-Helmholtz (KH) vortices that form in the nonlinear stage of the Kelvin-Helmholtz instability (KHI), based on multi-spacecraft measurements by Cluster at the dusk flank magnetopause during northward interplanetary magnetic field (IMF) periods. With the help of a three-dimensional MHD simulation of the KHI, signatures expected in the KH vortices at the magnetopause, namely, the magnetosheath plasma intruding into the magnetosphere, vortical plasma flow, and magnetic field perturbation pattern associated with the vortices, have been identified. In addition, plasmas of solar wind origin are present in the vicinity of the rolled-up vortices and on the magnetospheric side of the magnetopause. It is getting increasingly clear from theoretical studies that transport of plasma is inevitable in the rolled-up KH vortices. Thus our observations are precisely consistent with the scenario that, under northward IMF conditions, the KHI leads to the formation of the low-latitude boundary layer (LLBL) on the flanks. From comparison between measurements and simulation studies, the thickness of the KHI-associated LLBL is estimated to be roughly 4 $R_E$. We discuss the significance of the results for the LLBL formation during northward IMF and raise remaining questions concerning the magnetopause KHI.
DE: 7843 Numerical simulation studies
DE: 7859 Transport processes
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2752 MHD waves and instabilities
DE: 2764 Plasma sheet
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting