The plasma ion composition in the high-latitude magnetospheric boundary layer according to Prognoz-7 data

A mass analysis of the plasma in the high-latitude boundary layer (the plasma mantle) was made. Direct evidence was obtained that the ionosphere, similar to the solar wind, is a source of the plasmas in this region, filling it by ions (H+) and (O+). The number density of ionospheric ions (O+) in the mantle is usually several percent. During the disturbed periods it increases up to several tens of percent. Energies of these ions are several keV. The content of ions (O+) is usually much higher than that of ions (He+) that indicates the ionospheric but not plasmasphere origin of them. The mechanism of ion acceleration is probably such that it ensures an equal energy to all the ions independently or their mass. The content of ions (O+) correlates positively with the magnetospheric activity level.