Imaging the earth's magnetosphere: Effects of plasma flow and temperature

We simulate EUV images of the magnetosphere at 83.4 nm for cases where the plasma has a non-eero drift velocity with respect to the sun and variable plasma temperature. The solar emission in this region is dominated by b blend of nine gaussian shaped lines representing the O + triplet and the O ++ sextuplet contributions, (Meier, 1990a). The magnetospheric scattering crosssection profile includes only contributions from the O + triplet due to the low number density of O ++ compared to that of O +, (Chandler, 1987). The scattering rate has a complicated structure as a function of bulk velocity and does not possess any symmetry about zero. The scattering rate is reduced for most Doppler shifted cases compared to the case of zero bulk velocity, resulting in a much dimmer image. At some bulk velocities where the scattering cross-section of O + peaks at the brighter O ++ solar line profiles, larger scattering rates occur and the EUV image is brighter. Similarly, due to thermal Doppler spread the scattering rate decreases with increasing plasma temperature. Using a simple model for the O + ion number density we present simulated images of the magnetosphere including the radiation belt and plasma sheet for different viewing positions at distances of the order of 50 R e from the earth. We show that an EUV magnetospheric image of minimum reasonable quality may be obtained in 1000 s using an electronic imager with an aperture of 750 cm 2. Several comparative cases are shown to illustrate the simulated images in different perspectives and for a selection of bulk plasma velocities and temperatures.