Ion–neutral coupling in Earth's thermosphere, estimated from concurrent radar and optical observations above Alaska

摘要: Abstract During March–April 2011 a campaign of coordinated observations was undertaken between the Poker Flat Advanced Modular Incoherent Scatter Radar and Scanning Doppler Imager. These instruments provide horizontally resolved maps plasma neutral parameters in Earth's thermosphere. We report on data collected during campaign, use these to investigate two key aspects ion–neutral coupling, namely Joule heating collision frequency. Volumetric rates were often well correlated with measured ion temperature enhancements. The contribution wind dynamo observed positive when absolute horizontal magnetic field perturbation ( | Δ H ) less than approximately 40 nT, negative above that level. total momentum–transfer frequency estimated be 1 . 02 − 0.152 + 0.179 s at an altitude 260 km, which, for composition 75% atomic oxygen, yielded estimate O+–O 0 766 0.114 0.134