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arXiv · 2007.03231

Radio emission from negative lightning leader steps reveals inner meter-scale structure

B. M. Hare·O. Scholten·J. Dwyer·U. Ebert·S. Nijdam·A. Bonardi·S. Buitink·A. Corstanje·H. Falcke·T. Huege·J. R. Hörandel·G. K. Krampah·P. Mitra·K. Mulrey·B. Neijzen·A. Nelles·H. Pandya·J. P. Rachen·L. Rossetto·T. N. G. Trinh·S. ter Veen·T. Winchen
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Abstract

We use the Low Frequency ARray (LOFAR) to probe the dynamics of the stepping process of negatively-charged plasma channels (negative leaders) in a lightning discharge. We observe that at each step of a leader, multiple pulses of VHF (30~--~80 MHz) radiation are emitted in short-duration bursts ($<10\ \mu$s). This is evidence for streamer formation during corona flashes that occur with each leader step, which has not been observed before in natural lightning and it could help explain X-ray emission from lightning leaders, as X-rays from laboratory leaders tend to be associated with corona flashes. Surprisingly we find that the stepping length is very similar to what was observed near the ground, however with a stepping time that is considerably larger, which as yet is not understood. These results will help to improve lightning propagation models, and eventually lightning protection models.

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B. M. Hare, O. Scholten, J. Dwyer, U. Ebert, S. Nijdam, A. Bonardi, S. Buitink, A. Corstanje, H. Falcke, T. Huege, J. R. Hörandel, G. K. Krampah, P. Mitra, K. Mulrey, B. Neijzen, A. Nelles, H. Pandya, J. P. Rachen, L. Rossetto, T. N. G. Trinh, S. ter Veen, T. Winchen. 2020-07-07. Radio emission from negative lightning leader steps reveals inner meter-scale structure. https://doi.org/10.1103/physrevlett.124.105101

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