Leader properties determined with triggered lightning techniques

This paper presents current and electric field measurements from two triggered lightning flashes, 9519 and 9516, initiated by the "classical" and "altitude" technique, respectively, al Camp Blanding, Florida, in 1995. The current measurement for flash 9519 shows that the upward positive leader, initiated at the top of the grounded wire unreeled by the triggering rocket, propagates in a discontinuous pattern made of successive current pulses of tens to a few hundreds of amperes and separated by intervals of 20-25 mu s. The downward negative leader in flash 9516, initiated from the electrically floating conductor, has a velocity greater than 1.3 x 10(5) m s(-1), a stepping interval of 18 mu s, and step length of about 3-5 m; the associated peak currents inferred from the electric field steps are at least 600 A.