Chatanika/Triad observations of unstable ionization enhancements in the auroral F‐region

Preliminary results are presented from a campaign of coordinated measurements between the Chatanika radar and the TRIAD satellite to investigate production mechanisms responsible for localized high-latitude scintillations. The radar measured the latitudinal variations of plasma density and electric field while the satellite measured the field-aligned current distribution with latitude. This information was used to calculate the linear growth rate of the current convective instability. We find that field-aligned ionization enhancements, which are a common feature of the auroral F-region, are unstable, with instability growth times of ≤ 6 minutes. The observed plasma configuration, which was already gradient drift unstable on its poleward edge, was further destabilized by a field-aligned current of ∼ 0.8 µA/m². The presence of electron density irregularities produced in the unstable region was verified by observing VHF scintillations on the TRIAD telemetry signal.