Spacelab 2 Upper Atmospheric Modification Experiment over Arecibo. II - Plasma dynamics

Results are presented from an experiment performed on Spacelab 2 over Arecibo to study the neutral gas dynamics of supersonic flows in a rarefield atmosphere and to modify the plasma density by releasing chemically reactive vapors. Exhaust vapor was released at an altitude of 317 km, where the plasma density was 300,000/cu cm. Observations were made with high resolution incoherent scatter radar. A localized depletion formed in the ionosphere. The depletion fell and eventually disappeared within the bottomside F-region ionosphere. The dynamics of the evolution of the depletion are discussed. Optical and radar data are compared, setting an upper limit of 3 percent for the branching ratio to produce O(D-1) from dissociative recombination of CO(2+) and electrons.