Range ®nding of Alfve n oscillations and direction ®nding of ion-cyclotron waves by using the ground-based ULF ®nder

A new approach to the problem of direction and distance ®nding of magnetospheric ULF oscillations is described. It is based on additional information about the structure of geoelectromagnetic ®eld at the Earth's surface which is contained in the known relations of the theory of magnetovariation and magnetotelluric sounding. This allows us to widen the range of diagnostic tools by using observations of Alfve n oscillations in the Pc 3±5 frequency band and the ion-cyclotron waves in the Pc 1 frequency band. Preliminary results of the remote sensing of the magnetosphere at low-latitudes using the MHD ranger technique are presented. The prospects for remote sensing of the plasmapause position are discussed.