Observations of the Behavior of Multiple Channel Branches in Triggered Lightning

Several triggered lightning flashes have been obtained at Langmuir Laboratory in the 2009 and 2010 storm seasons. These flashes were observed with high-speed video, electric field mills, broadband electric field antennas, and Langmuir's Lightning Mapping Array, a 3-D VHF time-of-arrival system. One particular flash from 2010 shows more extensive low-altitude upward branching and exhibits multiple return strokes occurring on several different branches. In all recorded triggered flashes, the video reveals that one or more of the branches exhibit persistent luminosity for significant periods of time during the flash. In many of these flashes, dart leader-return stroke sequences appear on one or more unlit (or dimly lit) branches during times that other branches remain persistently illuminated. Some branches that are persistently illuminated during part of the flash later dim and commence dart leader-return stroke sequences, and vice versa.