High Speed Optical Observations of an Interesting Multi Branched Upward Lightning

Abstract:

We observed a multi branched upward lightning flash with one of its branches exhibiting an interesting progression mode never reported before. The branch progressed not though a regular leader, but through a series of recoil leaders with an average speed of 2.6×10⁴ ms^-1. The recoil leaders propagated bidirectionally near an existing main leader channel. When the lower end of a recoil leader connected with a main leader channel, the recoil leader upper end extended with branches. In addition, we found that a lightning discharge can move either from a recoil leader to an existing channel or from an existing channel to a recoil leader. Each recoil leader last about 0.24 ms on average, with the average interval of 2.6 ms. The initiation heights of the recoil leaders ranged from 251 m to 677 m above ground.