Remarks on lightning electromagnetics

摘要

The electromagnetic performances of a return-stroke are revisited, with special application to interference process involving aerial lines positioned in critical proximity to the channel. The usual superposition of elementary fields produced by current dipoles, resulting from a line integral performed along the channel, is critiqued. This with reference to the important pre-extinction instants in which the current front is rising. The ultimate intent is to offer, in alternative to previous procedures, an exact and simple formulation of the discharging channel model. Specifically, only the vertical component of the radiation field is found to be significantly involved in the coupling mechanism. However, mention is made to an improved version of the basic model which includes the depleting N-region, inside the thundercloud, to explain the quasi-static features of the LEMP. Last, possible departures in the induced effects produced by natural and triggered lightnings are also discussed. The fundamental aspects of such a complex subject are highlighted by a reasoned compilation of statements.