Traveling ionospheric disturbances derived from satellite-beacon observations at Graz and Neustrelitz

Simultaneous Faraday rotation measurements obtained at Graz and Neustrelitz during 1981 on the VHF signal from the GEO satellite Sirio are combined with differential Doppler measurements on polar-orbit satellites (obtained at Graz and Lindau) to investigate the wave structure of traveling ionospheric disturbances (TIDs). The data-reduction techniques employed make it possible to use Doppler data in place of the third-station Faraday rotation measurements normally required to obtain the large-scale TID structure. The results are presented graphically, and the feasibility of the analytical approach is demonstrated. The theoretical model is shown to provide insight into the nature of plasma/neutral-gas coupling in wave processes.