The PIs propose to use the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure to derive ionospheric conductance, electric filed, current and Joule heating maps for three disturbed equinox periods: 20-21 March 1990, 23-28 March 1991 and 28-29 March 1992. The first period is a Coupling Energetics and Dynamics of Atmospheric Regions (CEDAR) storm study interval for which we have begun initial data collection. The second period is one of considerable geophysical interest because it follows one of the largest flare events of solar cycle 22. Three Defense Meteorological Satellite Program (DMSP) satellites observed particle and field variations during this interval. For this interval the PIs will also acquire selected Fabry-Perot optical data and geosynchronous magnetospheric plasma analyzer data which we intend to correlate with high latitude-electrodynamic patterns. Considerable data also exist for the 28-29 March 1992 interval which was a Geospace Environmental Modelling (GEM) observational campaign. Because four DMSP spacecraft were operating during March 1992, the interval has the potential of producing the most comprehensive data set ever assembled for the study of large scale electrodynamic linkages from the solar wind to the magnetosphere, the ionosphere and ultimately to the neutral atmosphere. As in previous studies data will be acquired from DMSP particle and field measurements, NOAA particle measurements, Incoherent Scatter Radars, Coherent High Frequency Radars, and ground magnetic observatories from both hemispheres. These data will be assimilated to produce electric potential field distributions, horizontal and field-aligned current distributions and Joule heating and conductance distributions. The primary objectives for this study are: (1) providing explanation of deviations from large scale conjugacy in equinoctial convection patterns in terms of solar wind parameters, (2) documenting the temporal and spatial scale of high-latitude variations associated with significant changes of the IMF and correlating these variations with observations in the magnetosphere; (3) supporting new and ongoing coordinated storm studies (CEDAR and GEM) by providing a means for interpreting local observations in a global context.
