Characterization of Ionospheric Flow Patterns During Times of Unusual Auroral Activity Using DE and DMSP Data

摘要

This final report describes the work done by Dr. Marc Hairston and Dr. Rod Heelis on NASA SR&T grant NAGW-4411 studying the theta aurora using DE-1 ultraviolet imager data and DMSP particle data. This report covers the period from summer 1995 through summer 1996 along with a review of the previous work. Previous work on this grant looked at the time period from the launch of DMSP-F8 in June 1987 through the end of mission of DE-1 in summer 1991. Despite the sporadic and decreasing frequency of observations from DE-1 over this time period, we were able to identify six events for study where the DE-1 imager observed a theta aurora occurring during a period in which the DMSP-F8 satellite flew through the region of the aurora at an altitude of 800 km. We focused on the best two events where the theta aurora persisted for an extended period so that we could observe the DMSP particle signatures in both the hemisphere observed by DE-1 and in the other polar hemisphere immediately before or afterwards. These results were presented at the Fall 1994 meeting of the AGU. Initially we had hoped to expand on this work. However, further work showed that none of these events gave a clear enough signature in the DMSP data for us to identify a theta aurora in the hemisphere opposite to the hemisphere imaged by DE-1. Without that, there were no results from this work that were new enough to warrant publication. So instead we used the final year of the grant to work with our colleague, J. A. Cumnock on a similar project using DE data to study the evolution of theta auroras as a function of the IMF A paper from that work was published which acknowledged this grant and a copy of that paper is included with this final report.