Electrodynamics of the ionosphere from incoherent scatter: A review.

The incoherent scatter technique has played an important role since 1970 in the study of the electrodynamics of the ionosphere, thanks to its ability to measure the altitude profile of the ionospheric currents and to give access simultaneously to all electrodynamic parameters of the ionosphere: electric fields, neutral winds, conductivities, and electric current densities. The various calculation schemes involved in the derivation of this set of parameters are presented. The main results obtained up to now in three different latitude regions, from the auroral electrojets to the equatorial electrojet, are reviewed. The most promising developments of these studies in the near future are tentatively indicated. They appear to be of prime importance for progress toward a satisfactory description of electric current flows in the ionosphere-thermosphere system.