Electric field intensity of the lightning return stroke

From an examination of about 1000 electric field wave forms produced by lightning return strokes in 16 storms at distances between 20 and 100 km from an observation site at the Kennedy Space Center, Florida, a typical return stroke current wave form is derived. For this current wave form, the electric field intensity at distances between 0.5 and 100 km is computed for three values of return stroke velocity. The resultant curves for close lightning are compared with measured field wave forms. The transmission line return stroke model is used in all calculations since, as discussed, the Bruce-Golde model cannot account for the observed electric field characteristics.