Midday magnetopause shifts earthward of geosynchronous orbit during geomagnetic superstorms with Dst ≤ −300 nT
Article first published online: 28 AUG 2010
Copyright 2010 by the American Geophysical Union.
Journal of Geophysical Research: Space Physics (1978–2012)
Volume 115, Issue A8, August 2010
How to Cite
2010), Midday magnetopause shifts earthward of geosynchronous orbit during geomagnetic superstorms with Dst ≤ −300 nT, J. Geophys. Res., 115, A08230, doi:10.1029/2009JA014612., , and (
- Issue published online: 28 AUG 2010
- Article first published online: 28 AUG 2010
- Manuscript Accepted: 21 APR 2010
- Manuscript Revised: 2 APR 2010
- Manuscript Received: 28 JUN 2009
- geomagnetic superstorm;
- magnetopause inside geosynchronous orbit;
- conditions for superstorms
 Geomagnetic storm intensity, as measured by the Dst (SYMH) index, shows no limit as the solar wind dawn-to-dusk electric field increases. We show that the magnetopause around noon erodes earthward with increasing storm intensity. The panoramic geosynchronous BZ signatures for the magnetic storm groups with different intensity are differ significantly from each other. For superstorms with SYMH ≤ −300 nT, the magnetopause around noon erodes to inside the geosynchronous orbit, which causes the BZ reversal near local noon. The necessary conditions for superstorms with SYMH ≤ −300 nT to occur include the following: (1) interplanetary magnetic field (IMF) BZ < −27 nT lasts for at least ∼1 h; (2) solar wind dynamic pressure, Pd > ∼ 12 nPa; (3) the projected interplanetary electric field, EK − L > ∼30 mV/m.