Modeling of the Intracloud Lightning Discharge Radio Emission

Abstract

This paper aims at analyzing the broadband part of electromagnetic emission from thunderclouds in a frequency range of tens of kilohertz to hundreds of megahertz. A model of the intracloud lightning discharge formation is presented. The lightning formation is described as a stochastic growth of the branching discharge channels, which is determined by the electrostatic field. The dynamics of the electric field and of the charge distribution over the lightning structure is calculated deterministically. The effect of the initial charge density in the cloud and the parameters of the conducting channels on spatio-temporal characteristics of the currents and structure of the lightning discharge is studied. The discharge radio emission is calculated by summing up the radiation fields of each channel at the observation point. The standard model for a separate discharge current is adopted, and the electromagnetic radiation in the far zone is estimated. It is found that the obtained frequency spectra exhibit a universal power-law behavior. The results of the modeling agree with known experimental data.

Numerical Simulation of Stepping and Branching Processes in Negative Lightning Leaders

“…In this study, we assume a factor of 2 different threshold fields for positive (superscript “+”) and negative (superscript “‐”) polarities: , , , and at an altitude of 1 km, which corresponds to the height of our computational domain center above ground level. Similar streamer propagation fields were obtained experimentally by Allen and Mikropoulos () and theoretically estimated by Gallimberti et al () for positive polarity and adopted for both polarities in a number of lightning development models (Iudin & Davydenko, ; Iudin et al, , ; Mansell et al, , Tan et al, ). Note that in this study and apply only to the initiation of first collective streamer from the node representing the space stem and that, because of , the first streamer is always positive and, hence, is not needed in modeling the initiation of streamers from the space stem.…”