Resonant Alfvén Waves in the Lower Auroral Ionosphere: Evidence for the Nonlinear Evolution of the Ionospheric Feedback Instability

During the “Auroral Jets” experiment from Poker Flat, Alaska on 2 March 2017, two NASA sounding rockets were simultaneously launched into active auroral ionosphere. The equipped with instrumentation to measure DC and AC electric fields, magnetic energetic electrons, plasma density, neutral winds achieved apogees of 190 330 km. A prominent feature field observations is presence localized large-amplitude (±40 mV/m ±100 nT) small-scale (??? 1 km) Alfvén wave structures at altitudes as low 150 km in vicinity up- down-ward current regions. We interpret oscillations representing standing waves associated ionospheric resonator formed between ionosphere lower magnetosphere. components show signatures steepening correlation electron precipitation large variations background density. are discussed context nonlinear evolution feedback instability.