Topside Plasma Flows in the Equatorial Ionosphere and Their Relationships to F-Region Winds Near 250 km

Simultaneous measurements of F-region neutral winds near 250 km and topside field-aligned interhemispheric plasma flow near 600 km, made by the ionospheric connections satellite, allow the connection between these parameters to be observationally established for the first time. The largest variations in the topside plasma flows are seen as a function of season and are shown to depend on trans-equatorial neutral winds near the F peak in a manner that is essentially the same during the daytime and the nighttime for the solar minimum conditions that prevail in 2020. This finding is consistent with established principles of a servo model of the ionosphere for which both production and loss rates in the topside are specified by the O/N₂ ratio at the F-peak height. The intermediate relationships, describing how the neutral wind influences the F-peak height and how the O⁺ plasma pressure gradient across the equator influences the interhemispheric plasma flow are also investigated and found to be consistent with expectations.