RADAR AND AIRGLOW STUDIES OF F-REGION COMPOSITION AND DYNAMICS AT LOW LATITUDES

This thesis presents a series of studies investigating the composition and dynamics of the low latitude F-region ionosphere using airglow imagers and the Arecibo and Jicamarca incoherent scatter radars (ISRs), along with supporting instrumentation. Some dynamical aspects of the low latitude ionosphere are investigated. The ef-fects of a large-scale traveling ionospheric disturbance (TID) are studied. The TID characteristics are consistent with an atmospheric disturbance caused by high lati-tude Lorentz forcing associated with periodic substorms. Plasmaspheric coupling is necessary to explain the observed electron densities and airglow intensities. Evidence is presented for post-midnight uplifts during which the low latitude iono-sphere is lifted by tens of kilometers in mild events and by over a hundred kilometers in severe events. The uplifts are not caused by a reversal of the zonal electric field, instead occurring as a response to a decreasing westward field in conjunction with sufficient recombination and plasma flux. The midnight pressure bulge may play a role in the dynamics and the disturbance dynamo may enhance the uplifts. The spectral properties of daytime penetration fields are analyzed using ground