This award will support Dr. William L. Oliver of Boston University in a collaboration for three months with Prof. Susumu Kato and co- workers at the Radio Atmospheric Science Center of Kyoto University, Japan. They will use the Middle and Upper Atmosphere (MU) Radar at Shigaraki, Japan, and in particular its capability for ionospheric incoherent scatter studies, to 1) improve the statistical accuracy of the electrodynamics model by increasing the available data base; 2) develop a new model for velocity motion parallel to the magnetic field to study neutral-wind patterns; 3) use Doppler velocity as well as multi-beam density measurements to study ionospheric traveling waves; and 4) correlate current and past MU radar experiments with results of similar experiments conducted elsewhere. Understanding the behavior of the upper atmosphere in response to solar and particle inputs is one part of the overall problem of modeling changes in the total global atmosphere. The incoherent scatter radar technique provides data on the electrons, ions and neutral densities of the upper atmosphere and how these quantities change with various types of energy inputs. This project will permit Dr. Oliver to continue a study of the incoherent scatter radar data from the MU Radar at Shigaraki. The studies will take advantage of the increased data base to investigate seasonal and solar-cycle dependence of the electrodynamics of the ionosphere in relation to current models; study the vertical ion motions due to neutral winds; look for the influence of geomagnetic activity on the ionosphere; and compare the data from this station with other data taken throughout the world over the same time periods. The previous collaborative program initiated by this principal investigator has already increased the interaction between the Japanese and the rest of the world's incoherent scatter radar scientific community and this current project will strengthen and increase this activity.