On a criterion of the appearance of an upward leader from ground-based objects

Abstract

Results of an experimental study of processes forming an upward leader discharge from a grounded rod electrode in the electric field of an artificial cloud of charged water aerosol are presented. The transition of the streamer corona flash to an upward leader discharge was found to be of a probabilistic character and to be determined, first of all, not by the current amplitude, and not only by the flash charge passing through the stem of the pulse corona, but by a set of parameters: duration of the current passage at a rather high level and optimum value of the corona charge passed through the stem base. The range of radii of curvature of the rod-shaped lightning arrester tip (from 20 to 25 mm) at which the highest probability of the appearance of an upward leader is observed has been revealed.