Gravity Wave Dynamics and Tidal Interactions in the MLT and at the Bottomside F Layer and Their Potential Contributions to Neutral and Plasma Dynamics.

摘要

Research performed under this AFOSR contract targeted anticipated neutral atmosphere influences on the seeding, character, and statistics of equatorial plasma bubbles (EPBs). We employed several approaches, including (1) a large measurement program in Brazil, (2) analyses of correlative satellite data, and (3) numerical modeling of gravity wave dynamics that we expect to have significant influences on plasma dynamics in the ionosphere. Our SpreadFEx-2 field program focused on the onset of the EPB season, approximately October to December of 2009, 2010, and 2011 and employed much enhanced instrumentation compared to our 2005 SpreadFEx measurements. Enhancements included (1) FPIs measuring F-layer winds in Brazil, (2) 6300 imagers enabling tomography of EPB structures, and (3) CERTO beacon receivers for correlative studies with the C/NOFS satellite. The FPIs and imagers demonstrated the relative motions between neutral winds and EPBs to be a function of time and likely altitude. CHAMP data revealed the nature of the migrating tides at approximatley 400 km. their variations with season and the solar cycle, and the seasonal variations in gravity wave responses at approximately 300 km during 2010. Numerical studies of gravity waves addressed instability dynamics and penetration from specific sources that we expect to be especially important in the ionosphere.