Effect of pressure on the development of prebreakdown streamers

The initiation of streamers in a liquid under the application of negative impulse voltages to a needle-sphere gap is investigated. A square pulse is applied so that the prebreakdown streamer will not grow to breakdown. With application of pressure, the initial streamer is observed to collapse and disappear while the voltage remains on the tip. When the voltage is chopped, a new streamer appears which resembles the structure of the anode streamers. Its branches do not strictly follow the previous branches of the cathode streamer which injected the charge in the liquid. Using a simple model, approximately 11 nC is estimated to be injected into the liquid producing a charge density of 49 μC/cm ³