High-voltage atmospheric breakdown across intervening rutile dielectrics

Summary form only given. The electrical power grid, aircraft, and defense systems are potentially subject to damage from lightning strikes. Lightning arresters are high-voltage safety components used to mitigate damage to many critical systems by routing transient breakdown currents to ground. Typical arresters utilize high-permittivity dielectric materials, such as Rutile (a TiO₂ ceramic), to ensure breakdown occurs at a prescribed voltage and prevent a transient voltage pulse from affecting downstream components. Though widely used, the physical mechanisms for breakdown in lightning arresters are not well understood. Electrical discharge experiments are being conducted to develop predictive computational models of the fundamental processes of atmospheric breakdown in the vicinity of high-permittivity material interfaces. Discharge path imaging, optical spectroscopy, and electrical data are presented. Results are compared to static calculations using an ionization coefficient-based approach and Townsend-breakdown criteria for non-uniform fields and the observed breakdown path.