Chemical lasers with annular gain media

Resonators capable of extracting highly coherent energy from DF and HF chemical laser annular gain media have been under investigation for weapon application since 1974. This survey article traces the background of interest in these devices and describes the various concepts that have been experimentally and analytically investigate. A preferred concepts was selected for high power operation and is currently the subject of a high power demonstration program (Alpha). This paper also provides a summary of the Alpha Program including its history and hardware legacy.