HR: 0800h
AN: SM51C-0390    [Abstracts]
TI: On the Generation of Enhanced Sunward Convection and Transpolar Aurora in the High-Latitude Ionosphere by Magnetic Merging
AU: * Eriksson, S
EM: eriksson@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303 United States
AU: Baker, J B
EM: Joseph.Baker@jhuapl.edu
AF: Johns Hopkins University, Applied Physics Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723-6099 United States
AU: Petrinec, S M
EM: petrinec@star.spasci.com
AF: Lockheed Martin Advanced Tech Ctr, 3251 Hanover St, Palo Alto, CA 94304-1181 United States
AU: Elkington, S R
EM: scot.elkington@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303 United States
AU: Dunlop, M W
EM: M.W.Dunlop@rl.ac.uk
AF: Rutherford Appleton Laboratory, DIDCOT, Chilton, OX11 0QX United Kingdom
AU: Reme, H
EM: henri.reme@cesr.fr
AF: Centre d'Etude Spatiale des Rayonnements, 9 Avenue du Colonel Roche, Toulouse, 31028 France
AU: Greenwald, R A
EM: Ray.Greenwald@jhuapl.edu
AF: Johns Hopkins University, Applied Physics Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723-6099 United States
AU: Frey, H U
EM: hfrey@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720-7450 United States
AU: Ergun, R E
EM: ree@lasp.colorado.edu
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303 United States
AU: Balogh, A
EM: a.balogh@ic.ac.uk
AF: The Blackett Laboratory, Imperial College, Prince Consort Road, London, SW7 2BZ United Kingdom
AB: The IMAGE SI-12 instrument indicates a region of diffuse aurora poleward of the duskside Northern Hemisphere oval, while the IMAGE WIC instrument observes a transpolar auroral (TPA) feature at the polar cap boundary of the diffuse aurora during much of the 0110 UT to 0445 UT time interval on 16 December 2001. We here focus on the 0302 UT to 0312 UT period when the SuperDARN convection data display enhanced 800-1100 m/s sunward directed ionospheric flows near the TPA region in a four-degree wide region centered at 81$^{\circ}$ magnetic latitude between 14 MLT and 16 MLT. This flow channel seemingly drives a single dayside lobe cell with a convection reversal boundary near 84$^{\circ}$ and 14 MLT. At 0300 UT, the Cluster C1 S/C traverses the Northern Hemisphere duskside flank magnetopause at [X,Y,Z]=[-1.2,9.2,9.1] $R_{E}$ (GSM) where it encounters a localized density depletion region and a clear deflection of the bulk plasma velocity relative to the observed magnetosheath flow. The magnetic field and plasma velocity observed by C1 satisfy the Walen stress balance relation for a rotational discontinuity and the corresponding flow deflection dV suggests a merging site poleward and tailward of the spacecraft. The IMF magnitude as measured by ACE is 18 nT with a steady and favorable 45$^{\circ}$ clock angle (positive By and Bz) direction for merging in the vicinity of these duskside regions. The Tsyganenko T01 model maps the Cluster position to 75$^{\circ}$ and 14 MLT at 0130 UT or a few degrees equatorward of the ionospheric flow channel. Based on these data sets, we examine whether the active merging region on the magnetopause is consistent with the enhanced flow signatures observed by SuperDARN on 16 December 2001 and the IMAGE observations in these duskside high-latitude regions. An MHD simulation of this event puts these observations into a global context and is further used to map the Cluster location at the time of the plasma flow deflections to the ionosphere.
DE: 7835 Magnetic reconnection
DE: 2463 Plasma convection
DE: 2716 Energetic particles, precipitating
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2740 Magnetospheric configuration and dynamics
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting