Investigation of line streamers of dielectric surface by using dust figure techniques

The average propagation velocities of both positive and negative line streamers on a polyethylene-terephthalate (PET) sheet surface have been investigated by using the dust figure technique together with a line pulser. It is suggested that the dust figure technique is quite reasonable for studying the mechanism of the surface discharge because it permits the discrimination of the positive and negative charge distribution through powdering of bicolor particles. The polarity of residual charges on the locus of line streamers is the same as that of the applied pulse voltage. The back discharge causes some charges of the same polarity as that of the applied voltage to be repelled and to move toward the periphery of the locus of the line streamers. The average velocities of the line-streamer development under the conditions of an applied voltage of 7.5 kV, pulse durations ranging from 40 ns to 900 ns, and atmospheric pressure and room temperature range between 10⁶ cm/s and 10⁷ cm/s for both positive and negative cases. It is also shown that the inception voltages for both positive and negative line streamers are nearly the same, and are equal to 2.1 kV in the presented experiment