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Article Dans Une Revue Nature Année : 2019

Needle-like structures discovered on positively charged lightning branches

1 KVI Center for Advanced Radiation Technology
2 Radboud University [Nijmegen]
3 IMAPP - Institute for Mathematics, Astrophysics and Particle Physics
4 ASTRON - Netherlands Institute for Radio Astronomy
5 Astrophysical Institute, Vrije Universiteit Brussel
6 KIT - Karlsruhe Institute of Technology = Karlsruher Institut für Technologie
7 UR MALY - Milieux aquatiques, écologie et pollutions
8 Global Aerospace
9 SRON - SRON Netherlands Institute for Space Research
10 University of Southampton
11 Kapteyn Astronomical Institute [Groningen]
12 Jacobs University = Constructor University [Bremen]
13 RSAA - Research School of Astronomy and Astrophysics [Canberra]
14 Max Planck Institute for Astrophysics
15 Adran Ffiseg
16 Medstar Research Institute
17 TLS - Thüringer Landessternwarte Tautenburg
18 Leiden Observatory [Leiden]
19 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
20 USN - Unité Scientifique de la Station de Nançay
21 Department of Physics the George Washington University
22 Space Radio-Diagnostic Research Center [Olsztyn]
23 Center for Information Technology CIT
24 DAC - Department of Applied Chemistry
25 MPIFR - Max-Planck-Institut für Radioastronomie
26 CBK - Space Research Centre of Polish Academy of Sciences
27 Interactions Son Musique Mouvement
28 Rhodes University, Grahamstown
29 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
30 AlfA - Argelander-Institut für Astronomie
31 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
T. Trinh
  • Fonction : Auteur
A. Bonardi
  • Fonction : Auteur
P. Mitra
  • Fonction : Auteur
K. Mulrey
  • Fonction : Auteur
J. Rachen
  • Fonction : Auteur
T. Winchen
  • Fonction : Auteur
J. Anderson
  • Fonction : Auteur
R. Fallows
  • Fonction : Auteur
J. Eislöffel
M. Iacobelli
R. Pekal
  • Fonction : Auteur
R. Pizzo
H. Röttgering
M. Soida
  • Fonction : Auteur
M. C Toribio
  • Fonction : Auteur
A. van Ardenne
  • Fonction : Auteur
P. Zarka
  • Fonction : Auteur
  • PersonId : 935210

Résumé

Lightning is a dangerous yet poorly understood natural phenomenon. Lightning forms a network of plasma channels propagating away from the initiation point with both positively and negatively charged ends—called positive and negative leaders1. Negative leaders propagate in discrete steps, emitting copious radio pulses in the 30–300-megahertz frequency band2,3,4,5,6,7,8 that can be remotely sensed and imaged with high spatial and temporal resolution9,10,11. Positive leaders propagate more continuously and thus emit very little high-frequency radiation12. Radio emission from positive leaders has nevertheless been mapped13,14,15, and exhibits a pattern that is different from that of negative leaders11,12,13,16,17. Furthermore, it has been inferred that positive leaders can become transiently disconnected from negative leaders9,12,16,18,19,20, which may lead to current pulses that both reconnect positive leaders to negative leaders11,16,17,20,21,22 and cause multiple cloud-to-ground lightning events1. The disconnection process is thought to be due to negative differential resistance18, but this does not explain why the disconnections form primarily on positive leaders22, or why the current in cloud-to-ground lightning never goes to zero23. Indeed, it is still not understood how positive leaders emit radio-frequency radiation or why they behave differently from negative leaders. Here we report three-dimensional radio interferometric observations of lightning over the Netherlands with unprecedented spatiotemporal resolution. We find small plasma structures—which we call ‘needles’—that are the dominant source of radio emission from the positive leaders. These structures appear to drain charge from the leader, and are probably the reason why positive leaders disconnect from negative ones, and why cloud-to-ground lightning connects to the ground multiple times.
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Dates et versions

insu-02149526 , version 1 (13-08-2020)

Identifiants

Citer

B. M Hare, O. Scholten, J. Dwyer, T. Trinh, S. Buitink, et al.. Needle-like structures discovered on positively charged lightning branches. Nature, 2019, 568 (7752), pp.360-363. ⟨10.1038/s41586-019-1086-6⟩. ⟨insu-02149526⟩
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