The effect of tip curvature on the prebreakdown density change streamer in cyclo-hexane

The effect of tip curvature on the generation and propagation of prebreakdown density change streamers in cyclo-hexane was investigated. The streamer inception voltage increased with tip curvature, which was higher for a positive point than a negative one. The initial structure of the streamer was a single filament for both polarities in cyclo-hexane. The structure of the negative streamer changed from spherical to pagoda-like and bush-like with increasing applied voltage or tip curvature. A slim channel connecting the streamer with the needle tip was observed for a tip radius larger than 5 μm, but not for that smaller than 3 μm. For positive streamers, on the other hand, the structure changed from bush-like to filamentary with increasing tip curvature or applied voltage. There exists a critical tip curvature to generate a positive filamentary streamer. Both the length and the propagating speed of the streamer at its inception voltage increased with the tip curvature