Radio Emission Reveals Inner Meter-Scale Structure of Negative Lightning Leader Steps.
Phys Rev Lett
; 124(10): 105101, 2020 Mar 13.
Article
em En
| MEDLINE
| ID: mdl-32216418
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 µs). 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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MEDLINE
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En
Ano de publicação:
2020
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Article