Dependence of lightning current on resistance and radius of discharge plasma channel

Abstract

The current transmission characteristics of lightning discharge are closely related to lightning hazard mechanisms. The conductive properties of a lightning plasma channel were analyzed based on the spectra of nine negative cloud-to-ground lightning events recorded by a high-speed slit-less spectrograph and the theory of plasma conductivity. Combined with the information of synchronous electric field change caused by lightning, we estimated the peak current and corresponding current-carrying channel radius and further investigated the dependence of the discharge current on the resistance and radius of the discharge plasma channel. The results showed that there was a nonlinear relationship between the peak current and the resistance per unit length of the discharge channel. The radius of the current-carrying channel was positively correlated with the current intensity. Radius was an important parameter that affects the magnitude of the current. The electrical conductivity and the radius of the current-carrying channel have a coupling effect on the current transmission, which is the main factor determining the current transmission feature in the discharge plasma channel.