ION-DRAG EFFECTS IN THE THERMOSPHERE

Following a general description of the role of ion-drag in the F-region, especially as regards winds driven by electric fields (Sections 1 and 2), particular topics are dealt with: the geomagnetic control of thermospheric structure in low latitudes; the net eastward rotation of the thermosphere; and the correlation between different components of F-region plasma velocity (Sections 3-5). Concerning the last-named, there is some question whether the observations are entirely consistent with theory, and, since the general theory of ion-drag is believed adequate and the numerical data reasonably accurate (Section 6), there is a need for further study of what other processes might be involved. In addition, there is still a need for a comprehensive dynamical description of the equatorial thermosphere. © 1979.