COMMENTS ON RECENT OBSERVATIONS OF FAINTLY LUMINOUS FORMATIONS (FLF) CAPTURED USING PHANTOM HIGH-SPEED CAMERAS
During 2015, the high-speed camera network at Kennedy Space Center/Cape Canaveral Air Force Station was used to study a newly-reported optical phenomenon associated with the attachment process of lightning leaders to ground. This phenomena, termed the “Faintly Luminous Formation (FLF)” by researchers in the United States has significant implications on the definition of when and where the attachment process actually begins, important parameters that impact the design of successful lightning protection systems for assets and infrastructure. Five close (<1.5 km) lightning leader/return stroke sequences were simultaneously imaged by Phantom M310/V711 and V1610 highspeed cameras. In all cases, the M310/V711 cameras recorded FLF in a single pre-return stroke frame while the V1610 cameras recorded no evidence of FLF. The data provided in this paper indicates that FLF observations shown here and in recent studies in the United States and China may be digital camera artifacts as opposed to real lightning-related phenomena.