The characteristics and simulation of close leader/return stroke field change waveforms

Abstract

In order to reproduce the V‐shape structure characteristics of the close dart leader/return stroke field change, we employ two existing models, one for the “source charge” leader model and the other for MTLL return stroke model, both based on the assumption of uniform leader charge distribution along the channel and the charges deposited by the dart leader are completely neutralized by the following return stroke process. The simulated results show that the return stroke electric field is inversely related with the return stroke speed at early times (within few tens of microseconds of the beginning of the return stroke), while at later times (after 100 μs or so) the field is dominated by the deposited charge density component, the close electric field is independent of speed and the ratio of the leader field to the corresponding return stroke field tends to be equal to −1. Therefore, at early times (within few tens of microseconds) there is often some uncertainty regarding whether the charges deposited by the dart leader are completely neutralized by the following return stroke process based on the difference between the return stroke and the leader field on the ground. However, although several other return strokes models (TL, MTLE, TCS, BG and DU) exist, the results shown in the paper are strictly valid only for the used MTLL model.