Conjugate IS radar scans and space-borne imagery revealed an interaction between F-region plasma patches and ion upflow along the polar cap boundary.
Plasma patches found to modulate upflowing number flux at sites of nightside magnetic reconnection.
Unlike upflows in the main oval, polar boundary upflows have no causative relationship with ion or electron temperature, indicating a mechanism other than thermal expansion.
Semeter, J., C.J. Heinselman, J.P Thayer, R.A. Doe, and H.U. Frey, Ion upflow enhanced by drifting F-region plasma structure on the nightside polar cap boundary, Geophys. Res. Lett., accepted August, 2003.