Abstract
Knowledge of the upper atmosphere is essential to such varied applications as improving satellite communications, observing global change, flying high-altitude aircraft, and mitigating power line disruptions. The mesosphere/lower ionosphere is a particularly challenging region to study since it lies above the reach of airplanes and below that of most satellite orbits. Ground-based optical observations through a variety of instruments are a very powerful tool for accessing this region. One approach is to conduct observations of HF-induced airglow. We have designed and installed a telescopic imaging and photometric system at the High Frequency Active Auroral Research Program (HAARP) antenna array in Gakona Alaska in order to observe ionospheric fine structure in HF-induced airglow. In general, optical measurements of HF-induced airglow reveal ionospheric fine structure, provide a means of estimating electron energy distributions, and challenge current theories on HF wave/particle interaction.