HR: 0800h
AN: SH51B-1205    [Abstracts]
TI: Polar Crossing and Upstream of the Magnetopause and Bow Shock
AU: * Fennell, J F
EM: joseph.fennell@aero.org
AF: The Aerospace Corp., POBox 92957 MS:M2-259, Los Angeles, CA 90009 United States
AU: Roeder, J L
EM: james.l.roeder@aero.org
AF: The Aerospace Corp., POBox 92957 MS:M2-259, Los Angeles, CA 90009 United States
AU: Mulligan, T L
EM: tamitha.l.mulligan@aero.org
AF: The Aerospace Corp., POBox 92957 MS:M2-259, Los Angeles, CA 90009 United States
AU: Korth, A
EM: korth@linmpi.mpg.de
AF: Max-Planck-Institute fuer Sonnensystemforschung, Max-Planck-Strasse 2, Katlenburg-Lindau, 37191 Germany
AU: Grande, M
EM: m.grande@rl.ac.uk
AF: Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX110QX United Kingdom
AU: Friedel, R H
EM: friedel@lanl.gov
AF: Los Alamos National Laboratory, MS-D466, Los Alamos, NM 87545 United States
AB: The Cluster and Polar spacecraft have their apogees close in local time and in April 2001 these spacecraft were traversing the pre-noon regions. On 13 April, 2001 Polar's apogee was near 25 deg. magnetic latitude and it traversed the dayside plasma sheet and entered the magnetosheath and even the solar wind near apogee in conjunction with the passing of a CME associated interplanetary shock. The Cluster satellites were upstream of the bow shock during the 0400-1200 UT and provide the upstream solar wind data. At shock arrival, the solar wind pressure increased by a factor of three and the solar wind speed increased from 590 to 760 km/sec at Cluster, however Polar stayed inside the Earth's plasma sheet. Near 0935 UT the interplanetary field turned strongly southward and solar wind density and pressure rose by an order of magnitude. Polar first passed from the plasma sheet into the magnetosheath and, as the event continued, into the solar wind. Polar observed a burst of hot plasma and energetic particles near 1020 and 1040 UT as the field became less southward. Polar reentered the magnetosheath near 1100 UT as the dynamic pressure dropped rapidly and the IMF turned northward. Near 1130 UT Cluster observed an HFA and Polar, still in the magnetosheath, observed similar magnetic field signatures. Polar experienced a second short transition across the magnetopause near 1245 UT entering the magnetosheath for the next few hours. While in the solar wind, Polar observed transitory fluxes of very energetic ions which may be bow-shock associated, leakage from the compressed magnetosphere. However, the composition data taken both upstream and in the magnetosheath are free of O+ and He+ indicating these are most likely bow shock accelerated solar wind ions. We will discuss the combined Polar-Cluster observations during this event with emphasis on the composition changes of the energetic ions observed near and upstream of the magnetopause and the possible HFA detection by Polar in the magnetosheath.
DE: 2154 Planetary bow shocks
DE: 2728 Magnetosheath
DE: 2780 Solar wind interactions with unmagnetized bodies
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005