A subsequent positive stroke developing in the channel of preceding negative stroke and containing bipolar continuing current

• Published in: 2016 33rd International Conference on Lightning Protection (ICLP) pp. 1 - 7
• Main Authors: Yanan Zhu, Rakov, Vladimir A., Tran, Manh D., Weitao Lu
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.09.2016
• Subjects: bipolar lightning; Cameras; Clouds; Electric fields; Electric variables measurement; leader speed; Lightning; Phantoms; subsequent positive leader; Two dimensional displays
• DOI: 10.1109/ICLP.2016.7791409

A bipolar cloud-to-ground lightning flash was observed to exhibit two types of polarity reversal associated with the first two strokes separated by a not-unduly-long time interval of 70 ms. The first, negative stroke had a peak current of -101 kA and was followed by a second, positive stroke whose peak current was 16 kA. The latter contained a 122-ms long bipolar continuing current. The first two strokes, including the bipolar continuing current, occurred in the same channel to ground, whose imaged 2D length was 4.2 km. The occurrence of positive stroke in the negative-stroke channel is highly unusual. The 2D speed versus height profiles for the negative stepped leader of the first stroke and, for the first time, for the positive leader in the previously conditioned, first-stroke channel were examined and the average speeds were found to be 4.7×10 5 m/s and 7.2×10 5 m/s, respectively.