Comparison of H+ and He+ plasmapause locations based on the resurrected and reevaluated OGO-5 ion composition data base

Abstract

Orbiting Geophysical Observatory 5 (OGO 5) magnetospheric ion-composition data (H+, He+ and O+) have been retrieved from old magnetic tapes archived at the National Space Science Data Center (NSSDC). The highly compressed binary format was converted into a user-friendly ASCII format and these data have been made available online. We have inspected the reliability and consistency of this data set. Comparisons with the IRI-2012 climatological model and the FLIP theoretical model revealed a shift of absolute and relative ion densities with time. Here we have developed a correction procedure for the individual H+, He+ and O+ ion density measurements. We investigated plasmapause locations based on the density gradients in H+, and He+. The correlation coefficient between these locations was determined to be ~0.886 with the typical difference in L about 0.1. The electron density at the He+ plasmapause location based on the corrected data for all cases was >100cm−3.