Coupled electrodynamics in the nighttime midlatitude ionosphere

We describe a new, self-consistent scenario in which sporadic-E doublets, height bands of upward-displaced F-layer profiles, F-region plasma depletions, and radar backscatter plumes, are all manifestations of a coupled electrodynamical response by the nighttime midlatitude ionosphere to the presence of a traveling ionospheric disturbance (TID). We show that the response consists of (1) formation of image plasma structure in the E region, (2) initiation of a Hall-current-driven polarization process by the E-region plasma structure, and (3) mapping of the polarization electric field to the F region, where it strengthens the electrical properties of the TID that initiated the E-region processes. This scenario provides ready answers for several, hitherto puzzling, questions and a basis for new directions on this research topic.