This award will support a two-year U.S.-Japan cooperative science project between Professor William Oliver, Department of Electrical, Computer, and Systems Engineering and Center for Space Physics, Boston University, and Professor Shoichiro Fukao, Radio Atmospheric Science Center, Kyoto University. The project involves study of large-scale dynamical systems in the upper- atmosphere and ionosphere with MU (Middle and Upper atmosphere) radar at Shigaraki and the chain of ionosondes located at Japanese longitudes. The study will attempt to verify the existence of and distinguish between three different circulation systems indicated to exist by theory: the "normal" circulation system driven by solar photon heating at the sub-solar point and the "disturbance" circulation systems driven from the auroral and equatorial regions during periods of solar-wind disturbance of the earth's magnetic environment. During the summer of 1992 the investigators will attempt to verify the existence of these systems, identify their boundaries, and observe their latitudinal expansions and contractions during disturbance periods. During the summer of 1993 they will attempt to relate the ionospheric drift directions and gradients established by these circulations to theories of plasma instability generation to see if these conditions can provide seeding for the generation of the remarkable irregularities discovered by the MU radar in the ionosphere.
