On the development of a lightning leader model for tortuous or branched channels – Part I: Model description

An electrostatic model of the lightning leader channel for negative cloud-to-ground discharges was performed by using the Charge Simulation Method. This model is mainly intended to be applied on the stepped leader stage, even when assuming channel tortuosity or branches. It enables the calculation of the charge distribution along the channels and many other parameters such as electric fields, leader potential, average leader current and striking distance to flat ground. A description of the model is presented in Part I while the results for straight, tortuous and branched downward leader channels are given in Part II of this work.Furthermore, a procedure to generate random channels with or without branches and a macroscale tortuosity similar to the one observed in nature was developed. This generation allows simulating and evaluating the influence of the leader channel geometry on some important lightning parameters.