Potential distribution measurement of surface discharge developing on insulating material

A new method for measuring the transient potential distribution of surface discharge is developed. The measuring system consists of a BGO Pockels crystal, an Ar ion laser, a beam expander, a streak camera and a CCD camera. The potential profile of a surface discharge along a linear path of 50 mm in length is measured with high space and time resolution: 0.1 mm and 2 ns in minimum resolution. Electric field near the tip of a stepwise negative surface discharge is around 24 kV/cm. When the stepwise surface streamer stops its propagation, the potential distribution around the tip of it forms similar profile regardless of the order of occurrence