Shadowgraph Visualizations of Pulsed Discharge Phenomena in Pressurized Carbon Dioxide up to Supercritical Conditions*

In this study, pulsed discharge phenomena under high-pressure carbon dioxide including supercritical phase were visualized by means of shadowgraph method. A series of experiments is conducted by varying pressure from 0.1 to 15 MPa at the desired temperatures of 313, 308 and 298 K. The sequence of pulsed discharge plasma is observed by ICCD camera with Ar laser system. The observations show as follows: pre-breakdown phenomena with streamer; breakdown process and shock wave; collapse process and the observation of Rayleigh-Taylor instability.