Artificial auroras in the upper atmosphere: 2. Imaging results

On the ATLAS 1 mission (STS‐45, launched March 24, 1992) two experiments, AEPI (Atmospheric Emissions Photometric Imaging) and SEPAC (Space Experiments with Particle Accelerators) performed the first experiment in a series of active experiments intended to probe the atmosphere, ionosphere and magnetosphere with electron beams. The luminous artificial aurora generated by the electron beam interaction was detected and measured by AEPI both in white light and in a narrow wavelength band at 427.8 nm (peak intensity 5 kR). Modelling calculation showed that there was a significant contribution from emissions originating near the spacecraft. The spatial intensity distribution of the observed auroral patch is consistent with emission contribution from both high and low altitude regions. An extended tail in the direction of the shuttle wake was observed in the 427.8 nm channel, consistent with a decay time associated with the dissipation of the hot electron plasma.