Backward Darts and the Subsequent Scattered Discharges Occurring Along Lightning Positive Leader Branches

We used the LOw-Frequency ARray (LOFAR) to identify two new types of lightning discharges occurring along the tracks of earlier positive leaders. The first is a kind of intracloud dart leader that we call a “backward dart” whose behavior appears counterintuitive given the positive polarity of the channel, as they are negative dart leaders that initiate from the positive branches and propagate toward inactive positive leader tips, which is backward to the direction of normal negative dart leaders. In addition, we identify a second phenomenon consisting of bursts of spatially scattered VHF sources that lack directional propagation and only appear after dart leaders on the same positive leader channels, which we call “scattered discharges after darts.” Both of these phenomena are different from normal negative dart leaders, and thus at first seem counter-intuitive and difficult to explain. We propose a possible explanation involving local current cut-off and negative charge redistribution.

Duke Scholars

Author Steven A. Cummer Pierre R. Lamond Department of Electrical and Computer Engin ...