Streamer Initiation in Volume and Surface Discharges in Atmospheric Gases

It is generally acknowledged that once a highly conductive channel is established between two charged and conducting materials, electrical breakdown is well established and difficult to interrupt. An understanding of the initiation mechanism for electrical breakdown is crucial for devising mitigating methods to avoid catastrophic failures. Both volumetric and surface discharges are of interest. An effort is underway where experiments and theory are being simultaneously developed. The experiment consists of an impedance matched discharge chamber capable of investigating various gases and pressures to ten atmospheres. In addition to current and voltage measurements, a high dynamic range streak camera records streamer velocities. The streamer velocities are particularly valuable for comparison with theory. A streamer model is being developed which includes photo-ionization and particle interactions with an insulating surface. The combined theoretical and experimental effort is aimed at detailed comparisons of streamer development as well as a quantitative understanding of how streamers interact with dielectric surfaces and the resulting effects on breakdown voltage.