Influence of insulator profile on streamer propagation

In a uniform electric field the propagation of a positive single streamer along insulators made of PTFE has been studied. The basic properties of a streamer, namely the minimum electric field required for stable propagation together with the associated propagation velocity, and the dynamics of streamer growth were investigated. These streamer properties are influenced by the amplitude of the voltage, and therefore energy, used for initiation and by the profile of the insulator. The streamer growth was studied for applied electric fields greater than the minimum required for stable propagation. Along a smooth insulating surface a streamer system propagates with a 'surface' and an 'air' component, however, a step on the surface results, depending on its position, in a modification of this system.