Electric fields and zonal winds in the equatorial ionosphere inferred from CHAMP satellite magnetic measurements

Abstract

The Equatorial Electrojet (EEJ) produces a strong magnetic signal in measurements of the low-orbiting CHAMP satellite. Six years of data with more than 30,000 dayside equator crossings provide a unique data basis to study this current system. In addition to scalar measurements used in previous studies, we have also inverted vector magnetic field measurements to gain accurate meridional profiles of the eastward current in the equatorial region. By solving the relevant differential equation, the CHAMP-derived current profiles can be inverted for the driving zonal electric fields and zonal winds. As a result of this feasibility study, we suggest an inversion of the complete set of individual CHAMP EEJ current profiles, which will provide valuable new information on dayside electric fields and thermospheric winds at low latitudes. Copyright 2007 by the American Geophysical Union.