Latitudinal and vertical parameters of the equatorial electrojet from an autonomous data set

Abstract

The magnetic field expressions from the current ribbon and thick current versions of the continuous distribution of current density model and their merits have been presented. For the first time both the latitudinal and vertical parameters of the equatorial electrojet (EEJ) have been derived from the same set of data. The local noon and daytime means of certain key parameters of the EEJ are shown to be in good agreement with those from other sources. Selected local noon means include: peak current density j o , 10.58 ± 0.34 A/km 2; peak current intensity j o , 224 ± 9 A/km; total eastward current I +, 74 ± 5 kA ; EEJ current focal distance w, 300 ± 5 km ; half thickness at half of peak current density p, 7.0 ± 0.1 km; peak westward current location x m , 5.13 ± 0.08° dip latitude; and EEJ latitudinal extent L 1, 12 ± 1° dip latitude. The problem of model calculated landmark distances of EEJ being consistently shorter than observations, encountered by Onwumechili et al. [ J. geomagn. Geoelecl. 41, 443 (1989)] has been solved.