Streamer mechanism
Pre-coating and breakdown of dielectric liquids

Whether the liquid is subjected to a divergent field or a uniform field, whatever the form of the voltage wave (pulse, alternating, continuous), the predisruptive phenomena that most universally lead to the establishment of an electric arc are streamers: all kinds of luminous, branched figures have been given this name, usually originating in the vicinity of one electrode (generation phase) and then moving at high or very high speed towards the opposite electrode (propagation phase).

Depending on the shape and duration of the voltage wave, the streamer may stop or progress to the opposite electrode; as a general rule, when it reaches this electrode (or is very close to it), the arc occurs. Thus, the breakdown voltage of a liquid...