Return-Stroke Radiation by a Branched Channel: A Transmission-Line Discharge Model

This paper is concerned with the effects of branching in the lightning channel on the radiated fields of the return stroke. To model the current on the channel, we employ some recent results on the discharge of a transmission line that simulates the channel discharge. The effect of branches on the upward traveling return stroke pulse appears as a pulse-driven release of charge from the branch into the main channel. For the sake of simplicity, far-field radiation is obtained employing the modified transmission line (MTL) approximation for pulse propagation on the channel, which yields closed-form radiation.