Application of electromagnetic field expressions of accelerating charges to obtain electromagnetic fields of engineering return stroke models

Abstract

There are several approaches to describe the generation of return stroke current in lightning flashes, collectively referred to as return stroke models. Among these, engineering return stroke models are widely used to compute the electromagnetic fields generated by return strokes. These models are typically categorized into three types: current propagation, current generation, and current dissipation models. Each model type can be employed to describe the spatial and temporal variations of the return stroke current. Once these variations are defined, multiple methods are available to calculate the resulting electromagnetic fields, all of which yield equivalent results. One such method involves using electromagnetic field expressions for moving and accelerating charges. This paper illustrates the procedure for calculating the electromagnetic fields of return strokes using this approach. The procedure is demonstrated for all three categories of return stroke models: current propagation, current generation, and current dissipation.