Measurements of breakdown pressure wave and cathode and anode electric field up to electrical breakdown in PP film

Electrical breakdown of a polymer film generates the pressure wave, which is considered to include information about the breakdown initiation point. In this paper, we measured the breakdown pressure wave and the space charge distribution up to electrical breakdown by using pulsed electro-acoustic method in 30 /spl mu/m thick polypropylene film. We discussed electrical breakdown phenomena based on the breakdown pressure wave and the dependence of charge density at anode and cathode on applied field and temperature. These experimental results suggested that the electrical breakdown phenomena were affected by the hetero space charge accumulation and the initiation point of electrical breakdown corresponded to the position of hetero space charge accumulation in the 30 /spl mu/m thick polypropylene film.