Lightning electromagnetic field of a double-peaked channel-base current

Lightning electromagnetic field results are presented in this paper for negative discharges of the first return strokes into a perfectly conducting ground. For such strokes multi-peaked channel-base currents are experimentally measured usually having two emphasized peaks. If a new double-peaked function is chosen to approximate such a channel-base current then lightning electromagnetic field waveshapes differ from those obtained with the often used one-peaked current. In that case calculated results are in better agreement with lightning electromagnetic field measurements at different distances from the channel-base.