A distributed‐circuit return‐stroke model allowing time and height parameter variation to match lightning electromagnetic field waveform signatures

Abstract

[1] A new lightning return-stroke model based on a distributed circuit approach is formulated. The DNUTL (Dynamic Non-Uniform Transmission Line) model allows the computation of the time and height dependence of the channel parameters and contemplates the corona sheath and core losses representation. The capacitance and inductance of the channel are calculated by applying an original approach based on simple recursive equations. Electromagnetic fields generated by the DNUTL model at several distances from the channel base are presented for a given set of parameters. The obtained results indicate that the proposed model is able to successfully reproduce the main features of electromagnetic field waveshapes associated to natural and triggered lightning. Citation: Visacro, S., and A. De Conti (2005), A distributed-circuit return-stroke model allowing time and height parameter variation to match lightning electromagnetic field waveform signatures, Geophys. Res. Lett., 32, L23805,

Electric and Magnetic Fields Predicted by Different Electromagnetic Models of the Lightning Return Stroke Versus Measured Fields

“…Rakov and Uman [1], based on governing equations, have categorized return-stroke models into four classes: gas dynamic models [2], electromagnetic (EM) models [3], distributedcircuit models [4], [5], and "engineering" models [6]. Only EM models are considered in this paper.…”

Lightning strikes to tall objects: A study of wave interactions at the return‐stroke front using a nonlinear transmission line model

“…Both radii are selected so that the characteristic impedance of the channel is consistent with experimental data. If R = 0 and i c = 0, the assumption of a coaxial channel structure implies that the return-stroke current propagates unattenuated and undistorted with the speed of light c. Although the propagation of current and voltage pulses along a vertical lightning channel using transmission line theory would require the variation of both L and C with the vertical coordinate z [Baba and Rakov, 2005b;Visacro and De Conti, 2005], the assumption of a uniform transmission line to represent the channel enables a clearer identification of wave interactions occurring at the return-stroke front upon the arrival of current pulses transmitted from the tower to the channel. This assumption, which is not expected to significantly affect the results in qualitative terms, is also somewhat implicit in engineering return-stroke models such as the transmission line (TL) model [Uman and McLain, 1969] and its variants with exponential (MTLE) [Nucci et al, 1988] and linear (MTLL) [Rakov and Dulzon, 1987] current decay, even though these models should not be viewed as "transmission lines" in the sense of transmission line theory.…”

Overview of Recent Progress in Lightning Research and Lightning Protection

“…VI]). Visacro and De Conti [66] were apparently the first to develop an RLC lightning model based on a nonuniform TL approximation. In their model, L was assumed to be constant, while C and R were each a function of time.…”