ABSTRACT
There are two ways to detect auroral emissions in far ultraviolet (FUV) from a spacecraft using a fixed band-pass filter or spectrograph imaging. A fixed filter imager is a good candidate for auroral morphology study, whereas a spectrographic imager allows to reliably retrieve quantitative parameters of auroral particles (precipitating electrons and/or ions, the energy source of aurora). FUV observations of the aurora were obtained more than 30 years ago. These early observations demonstrated that the aurora could be detected against Earth’s FUV background emission. The Auroral Ionospheric Mapper instrument on the Defense Nuclear Agency’s HILAT satellite (P83-1) was designed to demonstrate the value to the Department of Defense of imaging the sunlit aurora. Auroral ionospheric characteristics (such as E-region peak density and height) an height integrated conductance can be estimated using FUV-based auroral measurements. FUV remote sensing can play an important role in developing the understanding of the fundamental processes that connect Earth’s atmosphere to Sun.
