Comments on “On the Concepts Used in Return Stroke Models Applied in Engineering Practice”

In the above paper [1], which is an important contribution to the lightning return stroke modeling literature, Cooray shows that any en-gineering model implying a lumped current source at the lightning channel base [any transmission-line (TL) type model] can be formu-lated in terms of sources distributed along the channel and progres-sively activated by the upward-moving return stroke front. This has pre-viously been demonstrated for one model [modified transmission-line model with exponential (MTLE) current decay with height] by Rachidi and Nucci [2]. The approach suggested by Cooray [1] has already been used by Rachidi et al. [3] to generalize five engineering models in order to take into account a tall strike object. A few comments on the above-mentioned paper, follow. Cooray [1, Appendix B2], states that the division of the total charge density into its“deposited”and“transferred”componentsgivenbyThot-tappillil et al. [4, Table 1] for the Diendorfer–Uman (DU) model is “no