Monochromatic all-sky observations and auroral precipitation patterns

An all-sky imaging system capable of fast monochromatic imaging at very low light levels is described; the system allows real time display of regions of proton precipitation and of soft and hard electron precipitation in the auroral zone. Sample data illustrate various auroral types previously classified from photometric data and/or from particle data from satellites. Time-lapse film throughout an entire night shows the position and intensity of plasma sheet precipitation, superposition of a harder electron aurora, the relative positions of proton aurora and diffuse aurora, and the changing character of the aurora as a function of local time and substorm activity. These patterns are discussed in terms of the substorm injection boundary model (McIlwain, 1974).