Middle and low latitude effects of auroral disturbances from incoherent-scatter

A review is presented of the major phenomena observed by incoherent-scattering and related to auroral disturbances or magnetic substorms in general. The first category of phenomena discussed are those which result from direct effects of perturbations in the magnetosphere projected downwards into the ionosphere along magnetic field lines, and includes the equatorial displacement of the midlatitude trough associated with plasmasphere erosion during substorms as well as strong midlatitude electric field disturbances observed during magnetically disturbed periods. The second category consists of perturbations of the neutral atmosphere at low and midlatitudes, and includes large-scale gravity waves propagating towards the equator as well as long-term modifications of the electron density distribution and dynamo electric field. Incoherent-scattering observations of these phenomena are described, and coordinated experiments are recommended for observing the ionospheric effects of magnetic storms.