Role of the ambient magnetic field B in the longitudinal variation of equatorial electrojet

Abstract

A review of studies of longitudinal variations of equatorial electrojet (EEJ) intensity confirms evidence of the longitudinal variation from POGO satellites data. This shows major peaks of EEJ intensity at 100oE and 190oE with a subsidiary peak at 190oE. The connection between EEJ intensity and the ambient magnetic field B has been probed with regression and power law analyses. These reveal no statistically significant relationship between the intensity of EEJ and B, and their fittings of observations are poor. Comparison of the longitudinal profile of B along the dip equator with average longitudinal profile of the zonal electric field Ey at the dip equator proves that on the average Ey is not independent of longitude as was assumed by earlier workers. It has been suggested that Joule heating of the atmosphere which depends on the square of B produces perturbations of ionospheric drift velocity, and that the perturbations contribute to the longitudinal variation of EEJ intensity.

Keywords: ambient magnetic field, equatorial electroject magnetic signature, longitudinal variation of equatorial electroject current.


(Global Journal of Pure and Applied Sciences: 2002 8(4): 517-528)