A comparison between N₂⁺4278-Å emission and electron flux in the auroral zone

This study utilizes data from the visual airglow experiment (VAE) and the low energy electron experiment (LEE) on board the Atmosphere Explorer D satellite. The 4278-Å N2+ surface brightness profile is measured as a function of angle along the satellite track by using a method which corrects for reflection from the ground below. This intensity is compared with the incident electron energy flux between 0.2 and 25 keV and plotted as a function of mean and total electron energy. The observed ratio of I4278/FE is 256 ± 125 R/erg cm−2 s−1, which is slightly higher than the value of ∼210 R/erg cm−2 s−1 predicted theoretically by Rees and Luckey [1974]. Excess 4278-Å emission on the southern edge of the aurora is shown to be a result of high-energy (>10 keV) proton precipitation. A general increase in the scatter of the data toward low mean electron energies is a possible indication of the presence of parallel electric fields below the altitude of the satellite (150–800 km).