This is a four-year research program utilizing measurements of ionospheric plasma drifts from the Upper Atmosphere Research Satellite incoherent scatter radar facilities at Arecibo and Jicamarca. One of the proposed research projects concerns the electrodynamic response of the low-latitude ionosphere to fundamental magnetosphere-ionosphere coupling processes during disturbed conditions. Improved plasma drift measurements from Arecibo together with high latitude, magnetospheric, and solar wind data will be used in combination with numerical simulations using global convection models. The objective is to obtain a quantitative understanding of the low latitude prompt penetration and disturbance dynamo electric fields due to the effects of the variation of the shielding efficiency with storm phase, interplanetary electric field (IMF), dynamic pressure, and IMF-By and, for the first time, due to substorms. Ultimately this is believed to lead to the development of a predictive low latitude empirical electric field model based on solar wind and flux parameters, which accounts for essential magnetospheric processes. Another project concerns the time dependent effects of the strongly disturbed low latitude electric fields on the plasma density distribution at higher latitudes. The latter will be investigated by means of the effects on mid and low latitude total electron content (TEC) as measured by a global network of Global Positioning System (GPS) receivers. A third project will examine the evolution of equatorial plasma bubbles in response to different seeding mechanisms and electrodynamic conditions by comparing the Jicamarca measurements with numerical simulations using the Naval Research Laboratory (NRL) three-dimensional plasma instability model. Finally, a research project will be carried out to quantify the season and solar flux dependent storm time coupling of ionospheric plasma drifts and thermospheric neutral winds. The goal of this project is to model empirically the altitudinal and longitudinal variation of the equatorial vertical drifts in the American sector. These altitudinal studies will include new Jicamarca drift measurements covering a much larger range of altitudes (up to about 1500-2000 km) than has been possible in the past.
The proposal includes a significant component of student training and participation. Graduate as well as undergraduate students will be supported under this grant and will participate in the research projects. Specifically, the students will be trained in highly advanced analysis techniques for the radar observations. In this way the project will contribute to building and sustaining this highly desirable expertise within the aeronomy community. University participation in the utilization of the UARS radar facilities is an important aspect of the facility program and this project will play an important role in meeting this goal. In addition, the proposed research involves widespread, cross-disciplinary collaborations with a broad range of scientists at several institutions.
