Simulation of lightning discharges: Influence of ground objects and positive leaders

Abstract

Cloud-to-ground (CG) lightning discharges in 3D domain were simulated using a stochastic dielectric breakdown model. The influence of ground objects on simulated lightning flashes was studied by introducing additional boundary conditions to the ground plane. It was observed that pointed structures on the ground have a higher probability of attracting simulated lightning discharges. An extension was introduced to the dielectric breakdown model to simulate the development of positive leaders that occur during CG lightning flashes. It was found that the height of the stepped leader tip above the ground (at the time when the positive leader initiation occurs) is dependent on the local electric field associated with the discharge step controlled by the parameter Ebreak. The height to the leader tip was found to decrease exponentially as Ebreak is increased.