Comments on "On the concepts used in return stroke models applied in engineering practice

For original paper see V. Cooray, ibid., vol.45, no.1, p.101-8, (2003). Cooray\´s paper is an important contribution to the lightning return stroke modeling literature. It shows that any engineering model implying a lumped current source at the lightning channel base - any transmission-line (TL) type model - can be formulated in terms of sources distributed along the channel and progressively activated by the upward-moving return stroke front. Comments are made on Cooray\´s division of the total charge density into its "deposited" and "transferred" components. The charge-density formulation in engineering return-stroke models by other ways is discussed.