Characteristics of the equatorial electrojet current in the central region of South America

R G Rastogi,H Chandra,K Yumoto,K Kitamura,M E James

doi:10.1186/bf03353126

Abstract

Abstract We describe here for the first time the morphology of the equatorial electrojet (EEJ) in the Central American Sector based on an analysis of the geomagnetic field components from six stations distributed on both sides of the dip equator along the 60°W geographic longitude sector. Diurnal and latitudinal variations in the horizontal and vertical components are shown to follow the Chapman model of EEJ. The horizontal component vector due to the ionospheric current aligned itself close to magnetic north, with a mean Declination of 10°W (ranging from 9°W to 14°W). There was a significant counter-electrojet effect before sunrise at stations close to the dip equator, suggesting late reversal of solar-quiet (S q) electric field in the morning hours. The observed variations in the magnetic meridional current did not seem to be associated with EEJ currents. The centre of the electrojet was around 0.25°S of the dip equator in the morning hours and shifted gradually to 1.5°S by the evening hours. Magnetic storms occurring during the midday hours produced an exceptionally large decrease in the H (horizontal component) field at stations close to the dip equator.

Highlights

Chapman (1951), in his citing of the earlier results of the latitudinal survey of the geomagnetic H field in Peru by A
A significant dip in BH was seen around the sunrise hours; this dip was most prominently at PRM and decreased in magnitude at stations farther from the equator
American Sector is based on the analyses of magnetic BH, BY and Z components from six geomagnetic field stations on both sides of the dip equator along 60◦W geographic longitudes for the period September–October 1994

Summary

Introduction

Chapman (1951), in his citing of the earlier results of the latitudinal survey of the geomagnetic H field in Peru by A. There would be no daily variations in the Y and Z fields at a station close to the centre of the electrojet current.

Results

Conclusion