Auroral electron distributions derived from combined UV and X-ray emissions

The Polar Ionospheric X-ray Imaging Experiment and the Ultraviolet Imager o n board the Polar satellite provide the first simultaneous global scale vie ws of the electron precipitation over a wide range of electron energies. By combining the results from these two remote sensing techniques we have dev eloped a method to derive the electron energy distributions that reproduce the true electron spectra from I to 100 keV and that call be used to calcul ate the energy flux in the energy range from 100 eV to 100 keV. The electro n energy spectra obtained by remote sensing techniques in three 5-min time intervals on July 9 and July 31, 1997, are compared with the spectra measur ed by low-altitude satellites in the conjugate hemisphere. In the energy ra nge from 90 eV to 30 keV the derived energy flux is found to be 1.03 +/- 0. 6 of the measured energy fluxes. The method enables us to present 5-min tim e-averaged global maps of precipitating electron energy fluxes with a spati al resolution of similar to 700 km. The study shows that the combination of UV and X-ray cameras oil a polar orbiting spacecraft enables comprehensive monitoring of the global energy deposition from precipitating electrons ov er the energy range that is most important for magnetosphere-ionosphere cou pling.