MAGNETOSPHERIC IMAGING OF HIGH-LATITUDE ION OUTFLOWS

High latitude ion outflows mostly consist of upward streaming O+ and H e+ emanating from the ionosphere. At heights above 1000 km, these flow s consist of cold and hot components which resonantly scatter solar ex treme ultraviolet (EUV) light, however, the ion populations respond di fferently to Doppler shifting resulting from the large relative veloci ties between the ions and the Sun. The possibility of optical detectio n of the Doppler effect on the scattering rate will be discussed for t he O+ (83.4 nm) ions. We have contrasted the EUV solar resonance image s of these outflows by simulations of the 30.4 nm He+ and 83.4 nm O+ e missions for both quiet and disturbed geomagnetic conditions. Input da ta for the 1000 km level has been obtained from the EICS instrument ab oard the Dynamics Explorer satellite. Our results show emission rates of 50 and 56 milli-Rayleighs at 30.4 nm for quiet and distributed cond itions and 65 and 75 milli-Rayleighs at 83.4 nm for quiet and distribu ted conditions, respectively, obtained for a polar orbiting satellite and viewing radially outward. We also find that an imager at an equato rial distance of 9 R(E) or more is in a favorable position for detecti ng ion outflows, particularly when the plasmapause is depressed in lat itude. However, an occultation disk is necessary to obscure the bright plasmaspheric emissions.