Observation of Ionization Wave Refraction at a Plane-Parallel Interface

Photo images of ionization waves in a disk chamber are presented in this paper. The disk chamber has a narrowing in the form of a ledge. Igniting a dc glow discharge, we observed for the first time refraction of ionization wave beams at their passage of the ledge. The refraction is similar to one of light at a plane-parallel plate. Analysis of the images confirmed the fulfillment of Snell's law for ionization waves.