N+ and Molecular Ions in Auroral Ion Upflows and Downflows

We present new direct ion composition observations of molecular and N⁺ ions in auroral ion upflows and downflows from the Imaging and Rapid-Scanning Mass Spectrometer (IRM) onboard Swarm-E (e-POP). Molecular ions, specifically N₂⁺, NO⁺ and O₂⁺, are observed at all e-POP altitudes (350-1500 km) at auroral latitudes during quiet times, but more frequently and in greater abundances during active and storm times, and their presence is correlated to an enhancement in the local N⁺ density. We compare the detailed characteristics of the observed N⁺ and molecular ions at quiet, substorm, and storm times, respectively, as well as their occurrence distributions, based on both detailed event and statistical data from the first five years of Swarm-E operation. We discuss the implications of the observed N⁺ and molecular ions on magnetosphere-ionosphere-thermosphere coupling, specifically their roles in atomic oxygen production in the auroral thermosphere and energetic upflowing N⁺ and molecular ions in the storm-time inner magnetosphere.