Modeling the lightning-channel formation based on the bipolar leader theory by an electrostatic-by-step approach allowing representing non-regular ground surfaces for applications related to lightning protection

A model for simulating the process of formation of the lighting channel in negative cloud-to-ground lightning, based on the bidirectional leader theory that allows calculating the evolution of the involved electrical quantities is presented. In particular, a new approach for modeling the effect of the ground by means of surface charges was included and substantially improved the quality of the model results. The tool that implemented the model was applied for developing certain results, including the threshold electric-field intensity required for initiation of the upward connecting leader from ground structures and estimates of striking distances. The striking-distance re-sults tend to be consistent with those provided by expressions based on observations of the real leaders with fast cameras, when their three-dimensional and inclined trajectories are considered.