Properties of VHF Electromagnetic Radiation Immediately Following the First Return Strokes

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F24%3A10493044" target="_blank" >RIV/00216208:11320/24:10493044 - isvavai.cz</a>
Result on the web
<a href="https://physics.mff.cuni.cz/wds/proc/pdf24/WDS24_03_f2_Kolinska.pdf" target="_blank" >https://physics.mff.cuni.cz/wds/proc/pdf24/WDS24_03_f2_Kolinska.pdf</a>
DOI - Digital Object Identifier
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Result language
angličtina
Original language name
Properties of VHF Electromagnetic Radiation Immediately Following the First Return Strokes
Original language description
Using the data from the SLAVIA magnetic loop sensor and the SAETTA lightning mapping array, we investigate electromagnetic signatures of 66 negative (-CG) and 26 positive (+CG) cloud-to-ground flashes. After the first return strokes (RS), we found distinct behaviour patterns depending on the flash polarity - a strong very high frequency (VHF) radiation, lasting for tens to hundreds of milliseconds, in all +CG flashes and nearly immediate decrease of VHF radiation in 59 -CG flashes. We suggest a possible explanation of this phenomenon by considering step-like propagation of a negative part of bidirectional leader starting at the top end of the positive lightning channel inside the thundercloud, emitting electromagnetic radiation across a broad frequency spectrum. However, 7 -CG flashes (11 % of cases) with unique characteristics exhibited an anomalous behaviour with a strong VHF radiation lasting for more than 2 ms after the RS. This may be linked to the preparatory processes for subsequent RS, or a presence of strong lower positive charge center in the thundercloud.
Czech name
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Czech description
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Project
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Continuities
S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection
WDS'24 Proceedings of Contributed Papers - Physics
ISBN
978-80-7378-520-8
ISSN
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e-ISSN
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Number of pages
7
Pages from-to
25-31
Publisher name
Matfyzpress
Place of publication
Praha
Event location
Praha
Event date
Jun 4, 2024
Type of event by nationality
EUR - Evropská akce
UT code for WoS article
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