Interrelation between ELF transients and ionospheric disturbances in association with sprites and elves

Hobara, Yasuhide; Iwasaki, Natsuko; Hayashida, Tsuyoshi; Hayakawa, Masashi; Ohta, Kenji; Fukunishi, H.

doi:10.1029/2000gl003795

Cited by 92 publications

(110 citation statements)

References 17 publications

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“…The only papers published on elve-related VLF perturbations so far are those of Hobara et al (2001Hobara et al ( , 2003 and Mika et al (2005). Hobara et al (2001Hobara et al ( , 2003 reported perturbations in association with 7 elves out of a total of 17.…”

Section: Electron Density Changes Induced By the Lightning Emp In Thementioning

confidence: 99%

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Early VLF perturbations observed in association with elves

Mika

Haldoupis

Neubert³

et al. 2006

Ann. Geophys.

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Abstract. VLF remote sensing is used to detect lowerionospheric electron density changes associated with a certain type of transient luminous events known as elves. Both ground-and satellite-based observations of elves are analysed in relation to VLF data acquired at various receiver sites in Europe, the United States and Antarctica. Ground-based observations were performed during the EuroSprite2003 campaign, when five elves were captured by low-light cameras located in the Pyrenees. Analysis of VLF recordings from Crete shows early VLF perturbations accompanying all of the elves. A large dataset consisting of elves captured by the ISUAL (Imager of Sprites and Upper Atmospheric Lightning) payload on Taiwan's FORMOSAT-2 satellite over Europe and North America has also been analysed. Early/fast VLF perturbations were found to accompany some of the elves observed over Europe. However, no VLF perturbations were detected in relation to the elves observed by ISUAL over North America. The present analysis -based on the largest database of optical elve observations used for VLF studies so far -constitutes evidence of processes initiated by the lightning EMP (electromagnetic pulse) causing electron density changes in the lower ionosphere in line with theoretical predictions. It also proves that sub-ionospheric electron density changes associated with elves can intrude to lower heights and thus perturb VLF transmissions. The possibility of VLF detection, however, depends on several factors, e.g., the distance of the elve from the receiver and the transmitterreceiver great circle path (GCP), the altitude of the ionised region and the characteristics of the VLF transmitter, as well as the EMP energy, which occasionally may be sufficient to cause optical emissions but not ionisation.

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Section: Electron Density Changes Induced By the Lightning Emp In Thementioning

confidence: 99%

“…Hobara et al (2001Hobara et al ( , 2003 reported perturbations in association with 7 elves out of a total of 17. However, there is some doubt if these perturbations were indeed caused by ionisation changes relating to elves.…”

Section: Electron Density Changes Induced By the Lightning Emp In Thementioning

confidence: 99%

Early VLF perturbations observed in association with elves

Mika

Haldoupis

Neubert³

et al. 2006

Ann. Geophys.

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“…The perturbation of ionospheric and mesospheric conductivity due to the sprite ionization column and sprite halos has been observed by measuring changes in the amplitude and phase of signals from distant narrowband VLF transmitters passing over a thunderstorm region (Dowden et al, 1994;Inan et al, 1995Inan et al, , 1996aInan et al, , b, 1997Inan et al, , 2010Molchanov et al, 1998;Hobara et al, 2001;Otsuyama et al, 2004;Neubert et al, 2008). The perturbations of VLF transmitter signals have been observed a few ms after the causative lightning stroke.…”

Section: Vlf and Elf Phenomena Associated With Spritesmentioning

confidence: 99%

“…The first peak corresponds to the causative lightning, whereas the second peak was found to be simultaneous in time with sprite luminosity and it appears to be proportional in amplitude to the brightness of the sprite. Based on the ELF field measurements, the charge moment change of the sprite can be extracted (Boccippio et al, 1995;Hobara et al, 2001Hobara et al, , 2006Hayakawa et al, 2004;Matsudo et al, 2009). In several cases the sprite current moments responsible for the ELF pulse were estimated to be of several hundred kA km (Cummer et al, 1998(Cummer et al, , 2006a.…”

Section: Vlf and Elf Phenomena Associated With Spritesmentioning

confidence: 99%

Underlying mechanisms of transient luminous events: a review

Сурков

Hayakawa

2012

Ann. Geophys.

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Abstract. Transient luminous events (TLEs) occasionally observed above a strong thunderstorm system have been the subject of a great deal of research during recent years. The main goal of this review is to introduce readers to recent theories of electrodynamics processes associated with TLEs. We examine the simplest versions of these theories in order to make their physics as transparent as possible. The study is begun with the conventional mechanism for air breakdown at stratospheric and mesospheric altitudes. An electron impact ionization and dissociative attachment to neutrals are discussed. A streamer size and mobility of electrons as a function of altitude in the atmosphere are estimated on the basis of similarity law. An alternative mechanism of air breakdown, runaway electron mechanism, is discussed. In this section we focus on a runaway breakdown field, characteristic length to increase avalanche of runaway electrons and on the role played by fast seed electrons in generation of the runaway breakdown. An effect of thunderclouds charge distribution on initiation of blue jets and gigantic jets is examined. A model in which the blue jet is treated as upward-propagating positive leader with a streamer zone/corona on the top is discussed. Sprite models based on streamer-like mechanism of air breakdown in the presence of atmospheric conductivity are reviewed. To analyze conditions for sprite generation, thunderstorm electric field arising just after positive cloudto-ground stroke is compared with the thresholds for propagation of positively/negatively charged streamers and with runway breakdown. Our own estimate of tendril's length at the bottom of sprite is obtained to demonstrate that the runaway breakdown can trigger the streamer formation. In conclusion we discuss physical mechanisms of VLF (very low frequency) and ELF (extremely low frequency) phenomena associated with sprites.

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“…The absence of observed optical phenomena (mesospheric optical emissions such as sprites) in the Hokuriku area (Sea of Japan side) indicates that the period was not extremely active in lightning as compared with the previous winter [Hobara et al, 2001]. Based on VLF subionospheric observation at Moshiri (Hokkaido) and Maizuru (near Kyoto) for two VLF transmitter signals (NWC (Australia) and NPM (Hawaii)), we have found the following; (1) Lightning discharges are found not only on the JapanSea side, but also on the Pacific side.…”

mentioning

confidence: 99%

Characteristic of subionospheric VLF perturbations associated with winter lightning around Japan

Otsuyama

Manabe

Hayakawa

et al. 2004

Geophysical Research Letters

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The VLF signature of ionospheric perturbations (Trimpis) associated with winter lightning around Japan has been investigated during a three‐month observation (December 2000 to February 2001). The absence of observed optical phenomena (mesospheric optical emissions such as sprites) in the Hokuriku area (Sea of Japan side) indicates that the period was not extremely active in lightning as compared with the previous winter [Hobara et al., 2001]. Based on VLF subionospheric observation at Moshiri (Hokkaido) and Maizuru (near Kyoto) for two VLF transmitter signals (NWC (Australia) and NPM (Hawaii)), we have found the following; (1) Lightning discharges are found not only on the Japan‐Sea side, but also on the Pacific side. Although more lightning was observed on the Pacific side of Japan, the Trimpi occurrence rate is more enhanced over the Sea of Japan. (2) Trimpis tend to occur only when the lightning activity is enhanced. (3) Trimpi occurrence rate shows no particular diurnal variation. (4) There is no significant difference in the Trimpi occurrence rate between + and − CG discharges. (5) The intensity of scattered signal (with respect to the unperturbed wave) is, in most case, ranging from −15 to −25 dB. These characteristics are discussed in terms of meteorological and lightning conditions.

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Interrelation between ELF transients and ionospheric disturbances in association with sprites and elves

Abstract: C), whereas a large lightning peak current (+223-+470 kA) (or slow-tail amplitude) leading to the strong EMP is necessary to initiate elves, but with rather small ionospheric disturbances.

Cited by 92 publications

References 17 publications

Early VLF perturbations observed in association with elves

Early VLF perturbations observed in association with elves

Underlying mechanisms of transient luminous events: a review

Characteristic of subionospheric VLF perturbations associated with winter lightning around Japan

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