Abstract
Two-dimensional structures of radiation emission behind strong shock waves in air are observed by using an image converter camera, and the photos are processed by an image processor. Strong shock waves are generated by a free-piston, double diaphragm shock tube. The shock speed are measured to be from 9 km/s to 11 km/s for the initial pressure of 13.3 Pa. It is shown that the double-peak characteristic becomes increasingly clear as the shock speed increases over 10 km/s. This can be mainly attributed to the increase of continuum radiation from free-free and free-bound transitions of electrons.
