Generalized Traveling Current Return Stroke Model with Current Reflections and Attenuation Along the channel

Abstract

The generalized traveling current source return stroke model (GTCS), Cvetic and Stanic [1995] is extended to take into account current reflections occurring at ground and at the upper end of the lightning channel, as well as current attenuation along the channel. The ground reflection factor and the top reflection factor of the current pulses are taken from the extended TCS model, Heidler [2007]. Current sources are placed along the activated length of the lightning channel, represented by the channel discharge function introduced in the GTCS model. Multiple reflections give rise to current waves moving up and down along the lightning channel. The total current is composed of the source current according to the original GTCS model and the reflected currents. The current along the channel can be represented as a sum of integrals of current sources along the channel. The traveling-current-source-type of “engineering” return stroke models can be regarded as special cases of the extended GTCS model. Moreover, for a convenient set of input parameters, the transmission-line-type of return stroke models can be also derived from the extended GTCS model. Simultaneously, the existence of the current source at the channel base, inherently built in all transmission-line-type of models is explained. This result is purely theoretical, since these two classes of “engineering” models are based on different physical pictures that describe processes in the lightning channel during the return stroke.