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An improved 3-D self-consistent stochastic stepped leader model

This paper presents an improved 3-D self-consistent stochastic model for downward stepped leader in negative cloud-to-ground lightning. The characteristics of a stepped leader, such as bending, step length, step pause interval and leader speed, are described by a series of equations and criteria, leading to a stochastic and step-wise growth of 3 dimensional leader channels. Lightning parameters, such as the evolution of leader charge distribution, corona sheath radius, core tip potential, ground electric field strength, total charge induced in the leader channel and striking distance to flat ground are computed and evaluated. The parameters predicted by the present model are found in relatively good agreement with those in literature. Furthermore, this model may serve as a virtual lab to study the attachment process of lightning striking to various structures for engineering building lightning protection analysis.