|
|
 |
|
|
Ann. Geophys., 23, 3549-3559, 2005
www.ann-geophys.net/23/3549/2005/
© European Geosciences Union 2005
Flux transfer events on the high-latitude magnetopause: Interball-1 observations
D. G. Sibeck1, G. I. Korotova2, V. Petrov2, V. Styazhkin2, and T. J. Rosenberg3
1Code 612.3, NASA/GSFC, Greenbelt, MD 20771, USA
2IZMIRAN, Troitsk, Moscow Region, 142190, Russia
3Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
Abstract. We present case and statistical studies of flux transfer events (FTEs)
observed by Interball-1 on the high-latitude magnetopause. The case studies
provide observations of FTEs in the cusp during periods of southward
interplanetary magnetic field (IMF) orientation and on the magnetopause
poleward of the cusp during periods of strongly northward IMF orientation.
We interpret the former in terms of reconnection on the equatorial
magnetopause and subsequent antisunward motion of FTEs into the cusps. We
interpret the latter in terms of bursty antiparallel merging on the
high-latitude magnetopause. A statistical survey demonstrates that events
observed equatorward of the cusp show a marked tendency to occur for
antiparallel (northward) magnetospheric and (southward) magnetosheath
magnetic field orientations, whereas events observed poleward of the cusps
tend to occur for either strongly parallel or antiparallel configurations.
We suggest that this discrepancy implies that events observed poleward of
the cusps originate both locally and on the equatorial magnetopause.
Finally, we use the sense of the bipolar signature and the prevailing
magnetic field orientation to demonstrate that almost all events move
antisunward, i.e. that at these latitudes pressure gradients determine the
motion of FTEs and not magnetic curvature forces.
Full Article in PDF (710 KB) |
|
|
