Investigations on transient currents associated with streamer propagation in dielectric liquids

A study of transient currents associated with the propagation of filamentary positive streamers in liquids is presented. Experimental measurements of currents in several selected liquids were analyzed with a simple model in which the channel is compared to a cylindrical conducting filament. Good agreement was found between theory and experiment, which indicates a rather high conductivity of the streamer filaments. An estimation of the charge carrier mobility in the filament was obtained, and it is concluded that the high current densities recorded are likely carried by electrons moving in a gaseous phase. The propagation of positive filaments in liquids is found to be similar to that of leaders in electronegative gases