Observations of unusual
current sheet structure on October 9 2003
J.
P. Eastwood (NASA GSFC), D. G. Sibeck (NASA GSFC), J. A. Slavin (NASA
GSFC), M. L. Goldstein (NASA GSFC), W. Keith (NASA GSFC), M. Hesse
(NASA GSFC), M. Sitnov (University of Maryland), E. A. Lucek (Imperial
College London, UK), A. Balogh (Imperial College London, UK)
We present high time resolution Cluster observations of the magnetotail
in the vicinity of the tail current sheet made on both October 2 and
October 9 2003. The October 2 event was unusual for the remarkably
large By magnetic field observed in the magnetotail. On this day, the
Interplanetary Magnetic Field By was similarly large. A structure
apparently consistent with a tailward moving X-line is analyzed using
the multipoint Cluster magnetic field data, and is found instead to be
consistent with an Earthward moving plasmoid.
Observations from October 9 2003 are also presented. On this day, the
Cluster spacecraft encountered a highly contained current sheet, the
whole crossing only lasting ~10 minutes, in conjunction with persistent
anti-sunward flows and numerous magnetic field dropouts. In particular,
strong bi-polar magnetic field signatures lasting a few seconds were
observed in the vicinity of these magnetic field dropouts. Cluster
multi-point analysis of the FGM data is used to determine the
orientation and motion of these structures. PEACE data is used to study
the properties of the electrons in these regions.