On the correlation between positive streamer shape and propagation in benzyltoluene

Presents an experimental study of streamer inception and propagation in benzyltoluene. In the liquid, positive filamentary streamers get a very specific shape: at low voltage, they are constituted of a single filament propagating up to the plane electrode. When the voltage is increased, the number of filaments emanating from the point increases, but both their stopping length and the probability to reach the plane electrode paradoxically decrease. Thus, over some voltage range, the breakdown probability decreases when the voltage is raised. This unusual effect can be explained from the shape of streamers: due to the electrostatic interactions between filaments, the field at their head decreases when their number increases as the voltage is raised.