Open AccessMidday magnetopause shifts earthward of geosynchronous orbit during geomagnetic superstorms with Dst ≤ −300 nT
Author(s) -
Li H.,
Wang C.,
Kan J. R.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009ja014612
Subject(s) - magnetopause , noon , geosynchronous orbit , solar wind , geomagnetic storm , physics , earth's magnetic field , magnetosphere , interplanetary magnetic field , geophysics , interplanetary spaceflight , solar cycle 22 , ionosphere , atmospheric sciences , daytime , magnetosheath , coronal mass ejection , magnetic field , astronomy , satellite , quantum mechanics
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 B Z 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 B Z reversal near local noon. The necessary conditions for superstorms with SYMH ≤ −300 nT to occur include the following: (1) interplanetary magnetic field (IMF) B Z < −27 nT lasts for at least ∼1 h; (2) solar wind dynamic pressure, P d > ∼ 12 nPa; (3) the projected interplanetary electric field, E K − L > ∼30 mV/m.