High speed video observation on random stepping and branching of negative leader

Based on the high speed images recorded at a frame rate of 180 kfps, the random stepping and branching behavior of negative lightning leader occurred in the natural atmosphere was analyzed in detail. The images clearly showed the luminous segments (indicative of space leader) that were separated from the leader tip and then their junction to the channel which resulted in enhanced luminosity. The occurrence of multiple space leaders (with different directions) from a same channel tip was an ordinary phenomenon in step process, and their concurrent connection with the already channel was the origin of leader branching, though most of the attempted branches failed to extend further and eventually extinguished. Those same-rooted branches exhibited alternate stepping during the initial extension.