SM51D-2585
Distinct sources of particles near the cusp and the dusk flank of the magnetosphere
Friday, 18 December 2015
Poster Hall (Moscone South)
C Philippe Escoubet1, Benjamin Grison2, Jean Berchem3, Karlheinz J Trattner4, Benoit Lavraud5, Frederic Pitout5, Jan Soucek6, Robert L Richard3, Harri E Laakso1, Arnaud Masson7, Malcolm W. Dunlop8, Iannis S Dandouras5, Henri Rème9, Andrew Neil Fazakerley10 and Patrick W Daly11, (1)ESTEC, Noordwijk, Netherlands, (2)Institute of Atmospheric Physics ACSR, Praha 4, Czech Republic, (3)University of California Los Angeles, Los Angeles, CA, United States, (4)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (5)IRAP, Toulouse, France, (6)Academy of Sciences of the Czech Republic, Prague, Czech Republic, (7)European Space Agency, SRE-O, Villanueva De La Can, Spain, (8)Rutherford Appleton Laboratory, Didcot, United Kingdom, (9)University of Toulouse, UPS-OMP, IRAP, Toulouse, France, (10)University College London, London, United Kingdom, (11)Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany
Abstract:
At the magnetopause, the location of the magnetic reconnection sites depends on the orientation of the interplanetary magnetic field (IMF) in the solar wind: on the dayside magnetosphere for an IMF southward, on the lobes for an IMF northward and on the flanks for an IMF in the East-West direction. Since most of observations of reconnection events have sampled a limited region of space simultaneously it is still not yet know if the reconnection line is extended over large regions of the magnetosphere or if is patchy and made of many reconnection lines. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side where we observe multiple sources of reconnection/injections. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed lower than usual around 280 km/s with the density of order 5 cm-3. The four Cluster spacecraft had an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. Using the time of flight technique on the upgoing and downgoing ions, which leads to energy dispersions, we obtain distances of the ion sources between 14 and 20 RE from the spacecraft. The slope of the ion energy dispersions confirmed these distances. Using Tsyganenko model, we find that these sources are located on the dusk flank, past the terminator. The first injection by C3 is seen at approximately the same time as the 2nd injection on C1 but their sources at the magnetopause were separated by more than 7 RE. This would imply that two distinct sources were active at the same time on the dusk flank of the magnetosphere. In addition, a flow reversal was observed at the magnetopause on C4 which would be an indication that reconnection is also taking place near the exterior cusp quasi-simultaneously. A three-dimensional global magnetohydrodynamic (MHD) simulation will be used to determine the global topology of the magnetic field during the event.
