Investigation of structure and transport processes in the high latitude ionospheric plasma using ground based and airborne digisondes

The Digisonde 256, an advanced ionospheric sounder, is a new and exciting tool for obtaining important ionospheric information. Like a conventional ionosonde, the Digisonde yields vertical electron density profiles. However, the antenna arrangement and sophisticated data handling system also permits plasma drift velocities to be derived from the ionospheric reflections. The F-region plasma drifts perpendicular to the magnetic field at the E x B velocity, and electric fields can therefore be deduced from the Digisonde drift measurements. This final report describes the development of the drift analysis techniques and highlights some of the exciting scientific results obtained by the Air Force Digisonde network, including the Airborne Ionospheric Observatory (AIO) of the Geophysics Laboratory. Digisonde data have been applied to the study of large scale ionospheric features such as high latitude convection, polar cap patches, sun aligned arcs, and the midlatitude trough.