Comments on "The EM field of an improved lightning return stroke representation"

V. Amoruso and F. Lattarudo (see ibid., vol.35, p.317-28, Aug. 1993) claim to produce valid field expressions, on the surface of a finitely conducting Earth, for a lightning return stroke using a TL (transmission line) representation for the current. The present author comments on their surface field calculation. His main concern is how they approximate the exact vector potential in the form they quote from his book (Wait 1962). Since their subsequent development is based on these approximated near- and far-field forms, it is important that the matter be clarified.<>