HR: 1340h
AN: SM43A-1069    [Abstracts]
TI: Cluster Observations of the Magnetospheric Low-Latitude Boundary Layer and Cusp During Extreme Solar Wind and Interplanetary Magnetic Field Conditions: 10 November 2004 ICME and Statistical Survey.
AU: Bogdanova, Y V
EM: jb@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London, Holmbury St.Mary, Dorking, RH5 6NT, United Kingdom
AU: Owen, C J
AF: Mullard Space Science Laboratory, University College London, Holmbury St.Mary, Dorking, RH5 6NT, United Kingdom
AU: Siscoe, G
AF: Boston University, Center For Space Physics, 725 Commonwealth Avenue, Boston, MA 02215, United States
AU: Fazakerley, A N
AF: Mullard Space Science Laboratory, University College London, Holmbury St.Mary, Dorking, RH5 6NT, United Kingdom
AU: Dandouras, I
AF: Centre d'Etude Spatiale des Rayonnements, 9 avenue du colonel Roche, Cedex-4, Toulouse, 31028, France
AU: Marghitu, O
AF: Institute for Space Sciences, P.O.Box MG-23, Bucharest-Magurele, Bucharest, 76900, Romania
AU: Marghitu, O
AF: Max-Planck Institute for Extraterrestrial Physics, Giessenbachstraße, Garching, 85748, Germany
AU: Kaymaz, Z
AF: Istanbul Technical University, Faculty of Aeronautics and Astronautics, Maslak, Istanbul, 34469, Turkey
AU: Reme, H
AF: Centre d'Etude Spatiale des Rayonnements, 9 avenue du colonel Roche, Cedex-4, Toulouse, 31028, France
AU: Lucek, E A
AF: Imperial College London, Blackett Laboratory, Prince Consort Road, London, SW7 2BW, United Kingdom
AU: * Coates, A J
AF: Mullard Space Science Laboratory, University College London, Holmbury St.Mary, Dorking, RH5 6NT, United Kingdom
AB: We present a study of the magnetospheric cusp response to extreme external parameters during passage of the ICME over the Earth on 10th November 2004, based on Cluster observations of the plasma properties inside the low-latitude boundary layer (LLBL)/cusp region in the dawn sector of the southern hemisphere. The Interplanetary Magnetic Field (IMF) is strongly equatorial, mostly due to the dominant dawn-dusk component. Under these conditions, occurring at the same time as pulses of solar wind dynamic pressure, the observations are very complicated. However, we suggest that in the polar region of the southern hemisphere, Cluster cross two LLBLs/cusps, spatially separated by polar cap plasma. The first LLBL/cusp is formed due to anti-parallel reconnection in the dusk sector of the southern hemisphere and the second is formed due to anti-parallel reconnection in the dawn sector of the northern hemisphere. The second LLBL/cusp is located at extremely low latitude, less than ~66.3deg ILAT. A statistical study of the location of the LLBL/cusp equatorward boundary during the ICME events on 28-29 October 2003 and 7-10 November 2004 is performed. During extreme conditions the LLBL/cusp position is off- set by -7deg ILAT from the location under normal conditions, which might be explained by the influence of the high solar wind dynamic pressure. The LLBL/cusp moves equatorward with increasing southward and northward IMF. However, the LLBL/cusp position under strong southward IMF is more poleward than expected from previous studies which could indicate some saturation in the dayside reconnection process or enhancement of the nightside reconnection rate. The LLBL/cusp position under strong northward IMF is extremely low and does not agree with the location predicted in previous studies. For the events with solar wind dynamic pressure more than 10 nPa, the LLBL/cusp position does not depend on the solar wind dynamic pressure. This might indicate some saturation in the mechanism of how the LLBL/cusp location depends on the solar wind dynamic pressure.
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 2724 Magnetopause and boundary layers
DE: 2740 Magnetospheric configuration and dynamics
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting