Satellite Data Analysis to Investigate the Horizontal Ion Density Gradients in the Lower Ionosphere

Abstract

Abstract : The final report is on the analysis of the data obtained from a satellite measurement program to investigate the characteristics and causes of horizontal ion density gradients in the F-region ionosphere. Data from the orbits prior to 225 of the OVI-18 satellite are analyzed here. The OVI-18 satellite was launched on 18 March 1969 into a polar orbit with apogee at 590 km and perigee at 469 km. Although the vehicle failed to achieve its desired earth-orientation, much valuable ion, electron and energetic particle data were obtained. Many gradients were observed in the ion density, some of which correlated with energetic particle precipitation in the auroral zones. It is concluded that precipitated particles in the night auroral zones give rise to significant ionization gradients at low altitudes and that these effects, although reduced in magnitude, are also seen at altitudes near 500 km, well above the F2 peak in ionization.