Average terrestrial ring current derived from AMPTE/CCE-CHEM measurements

Abstract

The present study attempts to analyze the average ring current density and pressure in the magnetospheric equatorial plane (as a function of geocentric distance and local time) based on the AMPTE/CCE-CHEM proton distributions according to two different AE ranges, corresponding to a low (AE<100 nT) and a moderate (100 nT <4.5) and an extended westward current at higher altitudes. The westward current is always stronger than the eastward current. Moreover, the ring current system is a function of magnetic local time, exhibiting a noon-midnight asymmetry in general, as well as a function of geomagnetic activity exhibiting an enhancement of about 20% during active times (in midnight-dusk region only). The location of the total current peak in the midnight sector is at about MLT=2300, and its changes with magnetic activity are interpreted as an effect of the particles injection from the tail during the storms/substorms. The derived current values are compared to previous model predictions and observations. Copyright 1997 by the American Geophysical Union.