ABSTRACT
Recent measurements have shown that lightning leader pulses have very fast rise times. Characteristic times for the rise of as small as a little less than 30 ns have been observed. Considering the nature of these leader pulses, an approximate model is obtained. This model is based on an equivalent transmission line as sometimes used in antenna theory. A corona which increases the capacitance per unit length is assumed to form around the central arc channel. Letting the corona radius be governed by a simple breakdown model, a nonlinear wave equation is obtained for the arc. Solving this equation one obtains velocities of the order of 108 m/s and currents of the order of 15 kA; this agrees well with the data.
