RANGE FINDING OF ALFVEN OSCILLATIONS AND DIRECTION FINDING OF ION-CYCLOTRON WAVES BY USING THE GROUND-BASED ULF FINDER

A new approach to the problem of direction and distance finding of mag netospheric ULF; oscillations is described. It is based on additional information about the structure of geoelectromagnetic field at the Ear th's surface which is contained in the known relations of the theory o f magnetovariation and magnetotelluric sounding. This allows us to wid en the range of diagnostic tools by using observations of Alfven oscil lations in the Pc 3-5 frequency band and the ion-cyclotron waves in th e Pc 1 frequency band. Preliminary results of the magnetosphere at low -latitudes using the MHD ranger technique are presented. The prospects for remote sensing of the plasmapause position are discussed.