Radio emission from negative lightning leader steps reveals inner meter-scale structure. (arXiv:2007.03231v1 [physics.ao-ph])
<a href="http://arxiv.org/find/physics/1/au:+Hare_B/0/1/0/all/0/1">B. M. Hare</a>, <a href="http://arxiv.org/find/physics/1/au:+Scholten_O/0/1/0/all/0/1">O. Scholten</a>, <a href="http://arxiv.org/find/physics/1/au:+Dwyer_J/0/1/0/all/0/1">J. Dwyer</a>, <a href="http://arxiv.org/find/physics/1/au:+Ebert_U/0/1/0/all/0/1">U. Ebert</a>, <a href="http://arxiv.org/find/physics/1/au:+Nijdam_S/0/1/0/all/0/1">S. Nijdam</a>, <a href="http://arxiv.org/find/physics/1/au:+Bonardi_A/0/1/0/all/0/1">A. Bonardi</a>, <a href="http://arxiv.org/find/physics/1/au:+Buitink_S/0/1/0/all/0/1">S. Buitink</a>, <a href="http://arxiv.org/find/physics/1/au:+Corstanje_A/0/1/0/all/0/1">A. Corstanje</a>, <a href="http://arxiv.org/find/physics/1/au:+Falcke_H/0/1/0/all/0/1">H. Falcke</a>, <a href="http://arxiv.org/find/physics/1/au:+Huege_T/0/1/0/all/0/1">T. Huege</a>, <a href="http://arxiv.org/find/physics/1/au:+Horandel_J/0/1/0/all/0/1">J. R. Hörandel</a>, <a href="http://arxiv.org/find/physics/1/au:+Krampah_G/0/1/0/all/0/1">G. K. Krampah</a>, <a href="http://arxiv.org/find/physics/1/au:+Mitra_P/0/1/0/all/0/1">P. Mitra</a>, <a href="http://arxiv.org/find/physics/1/au:+Mulrey_K/0/1/0/all/0/1">K. Mulrey</a>, <a href="http://arxiv.org/find/physics/1/au:+Neijzen_B/0/1/0/all/0/1">B. Neijzen</a>, <a href="http://arxiv.org/find/physics/1/au:+Nelles_A/0/1/0/all/0/1">A. Nelles</a>, <a href="http://arxiv.org/find/physics/1/au:+Pandya_H/0/1/0/all/0/1">H. Pandya</a>, <a href="http://arxiv.org/find/physics/1/au:+Rachen_J/0/1/0/all/0/1">J. P. Rachen</a>, <a href="http://arxiv.org/find/physics/1/au:+Rossetto_L/0/1/0/all/0/1">L. Rossetto</a>, <a href="http://arxiv.org/find/physics/1/au:+Trinh_T/0/1/0/all/0/1">T. N. G. Trinh</a>, <a href="http://arxiv.org/find/physics/1/au:+Veen_S/0/1/0/all/0/1">S. ter Veen</a>, <a href="http://arxiv.org/find/physics/1/au:+Winchen_T/0/1/0/all/0/1">T. Winchen</a>
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.
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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