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Ann. Geophys., 23, 445-460, 2005
www.ann-geophys.net/23/445/2005/
© European Geosciences Union 2005
Simultaneous in-situ observations of the signatures of dayside reconnection at the high- and low-latitude magnetopause
J. A. Wild1, S. E. Milan1, S. W. H. Cowley1, J. M. Bosqued2, H. Rème2, T. Nagai3, S. Kokubun4, Y. Saito5, T. Mukai5, J. A. Davies6, B. M. A. Cooling7, A. Balogh8, and P. W. Daly9
1Dept. of Physics & Astronomy, University of Leicester, Leicester LE1 7RH, UK
2CESR/CNRS, 9 Avenue du Colonel Roche BP 4346, 31028 Toulouse, Cedex 4, France
3Dept. of Earth & Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
4Solar-Terrestrial Environment Laboratory, Nagoya University, Toyokawa, Aichi 442, Japan
5Institute of Space & Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan
6Rutherford Appleton Laboratory, Didcot, Oxfordshire, OX11 0QX, UK
7Formerly at: Astronomy Unit, Queen Mary, University of London, UK
8Blackett Laboratory, Imperial College, London SW7 2BZ, UK
9Max Planck Institute for Solar System Research, Katlenburg-Lindau, D-37191 Katlenburg Lindau, Germany
Abstract. We present magnetic field and particle data recorded by the Cluster and
Geotail satellites in the vicinity of the high- and low-latitude dayside
magnetopause, respectively, on 17 February 2003. A favourable conjunction of
these spacecraft culminated in the observation of a series of flux transfer
events (FTEs), characterised by bipolar perturbations in the component of the
magnetic field normal to the magnetopause, an enhancement in the overall
magnetic field strength, and field tilting effects in the plane of the
magnetopause whilst the satellites were located on the magnetosheath side of
the boundary. Whilst a subset of the FTE signatures observed could be
identified as being either normal or reverse polarity, the rapid succession
of events observed made it difficult to classify some of the signatures
unambiguously. Nevertheless, by considering the source region and motion of
flux tubes opened by magnetic reconnection at low latitudes (i.e. between
Cluster and Geotail), we demonstrate that the observations are consistent
with the motion of northward (southward) and tailward moving flux tubes
anchored in the Northern (Southern) Hemisphere passing in close proximity to
the Cluster (Geotail) satellites. We are able to demonstrate that a
multi-spacecraft approach, coupled with a realistic model of flux tube motion
in the magnetosheath, enables us to infer the approximate position of the
reconnection site, which in this case was located at near-equatorial
latitudes.
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