A new model for the primary process of electrical breakdown inliquids

A new model for the generation of electrical streamers in insulating liquids is proposed, It is based on the mechanical stress generated by the electric field and its influence on the cohesive properties of the liquid. In fields of 10⁸ to 10⁹ V m^-1 the stress is sufficient to enhance significantly the thermal generation of sub-microscopic rupture surfaces (holes) in the liquid which has solid-like properties in the short time of streamer development. Using the well-known Griffith concept of mechanically-generated crack propagation in solids, it is then argued that, when the population of sub-microscopic holes becomes sufficiently large, the same stress encourages macro-crack development which has all the hallmarks of streamer growth, In this model electrical discharges do not have a traditional primary role although they will have an important secondary role once macro-cracks have developed