Properties of VHF Electromagnetic Radiation Immediately Following the First Return Strokes

Kód výsledku v 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>

Výsledek na webu

<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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Jazyk výsledku

angličtina

Název v původním jazyce

Properties of VHF Electromagnetic Radiation Immediately Following the First Return Strokes

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Properties of VHF Electromagnetic Radiation Immediately Following the First Return Strokes

Popis výsledku anglicky

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.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

WDS&apos;24 Proceedings of Contributed Papers - Physics

ISBN

978-80-7378-520-8

ISSN

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e-ISSN

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Počet stran výsledku

7

Strana od-do

25-31

Název nakladatele

Matfyzpress

Místo vydání

Praha

Místo konání akce

Praha

Datum konání akce

4. 6. 2024

Typ akce podle státní příslušnosti

EUR - Evropská akce

Kód UT WoS článku

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