On a possible mechanism of space stem formation at the negative corona streamer burst periphery

Abstract It's a common knowledge for spark discharge researches that negative leaders in air always propagate in a step-wise manner. A new step forms when a space leader attaches to the primary negative one. Space leaders originate from small fusiform plasma formations which are called space stems. For now, there is no any established idea about how space stems form in conditions when the background electric field inside the negative corona volume is about three times less than the dielectric strength of air. In this study, we propose a new mechanism of space stem precursors formation which is based on the joint action of ionization and electron drifting processes occurring at the negative corona streamer burst boundary in the presence of strongly inhomogeneous stochastic electric field. It is supposed that electric field fluctuations are formed by chaotically positioned clusters of negative charge which can be considered as basic elements of spatio-temporal noise and are transported into the negative corona volume by negative streamer heads. The last are emanated from the newly-formed leader tip during the development of the negative corona streamer burst finishing the step-formation process. The model is applied to specify conditions, under which space stem precursor genesis is possible, and to analyze the peculiarities of proposed mechanism at different altitudes above sea level.