This project acquires measurements of the topside ionosphere using an incoherent scatter radar at Kharkov, Ukraine. This data, with simultaneous measurements from the Millstone Hill and Arecibo Observatories, contributes to the CEDAR/POLITE research program, which studies concentrations of atomic oxygen and hydrogen ions at altitudes above 400 km. Previous collaborative efforts between scientists at MIT and the Institute of the Ionosphere in Kharkov have incorporated the capabilities of the Ukrainian research facility into US research programs to study coupling between atmospheric layers. The Ukrainian facility provides high-quality data that suggests a significant longitude effect in the topside ion distribution. The POLITE campaigns aim to study the altitude at which hydrogen ions become more abundant than oxygen ions. Kharkov data from a POLITE campaign in February, 1996 shows this transition height to be less than 450 km altitude. In this project, MIT scientists work with the Kharkov staff to interpret these measurements and participate in future POLITE campaigns.
