Response of the mid-altitude cusp to rapid rotations of the IMF
Article first published online: 10 JUN 2006
Copyright 2006 by the American Geophysical Union.
Geophysical Research Letters
Volume 33, Issue 11, June 2006
How to Cite
2006), Response of the mid-altitude cusp to rapid rotations of the IMF, Geophys. Res. Lett., 33, L11107, doi:10.1029/2005GL025460., , , , , and (
- Issue published online: 10 JUN 2006
- Article first published online: 10 JUN 2006
- Manuscript Accepted: 28 MAR 2006
- Manuscript Revised: 2 MAR 2006
- Manuscript Received: 12 DEC 2005
 On 12 August 2003, the four Cluster spacecraft crossed the mid-altitude cusp one after the other a minute or two apart. Shortly after the cusp crossing, two of the Cluster observed three structures poleward of the cusp that appeared and grew in successive satellite passes. In these structures, high fluxes of low-energy magnetosheath-like ions and electrons are observed. The analysis of particle and magnetic field data reveals that it is the cusp region that moved back and forth over the spacecraft. We show that the cusp reacts extremely fast to rotations of the interplanetary magnetic field (IMF) and that each of the three northward turnings of the IMF is accompanied by a poleward displacement of the cusp. The latitudinal component of the cusp velocity at ∼5 Re altitude is estimated to be of the order of 30 km/s.