Possible persistent ionization caused by giant blue jets

Lehtinen, N. G.; Inan, U. S.

doi:10.1029/2006gl029051

Cited by 64 publications

(104 citation statements)

References 23 publications

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“…In the altitude range of interest, the numerical values of parameters, i.e. α d = 10 −7 −3×10 −7 cm 3 s −1 (Lehtinen and Inan, 2007) and N e0 = 6 × 10 4 cm −3 , give the estimate t r ∼ (1.7 − 5) × 10 2 s which is compatible with the observations.…”

Section: Vlf and Elf Phenomena Associated With Spritessupporting

confidence: 80%

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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Section: Vlf and Elf Phenomena Associated With Spritessupporting

confidence: 80%

Underlying mechanisms of transient luminous events: a review

Сурков

Hayakawa

2012

Ann. Geophys.

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“…[13] Time evolution of electron and ion densities from 20 to 120 km altitude is calculated using a five-constituent model, an extension of Glukhov et al's [1992] model to be applicable at altitudes <50 km [Lehtinen and Inan, 2007]. Electrons (N e ), negative ions (N À ), light positive ions (N + ), positive ion clusters (N x + ) and heavy negative ions (N x À ) have densities described by:…”

Section: Discussionmentioning

confidence: 99%

“…The analysis of flare impact and resulting ionization used here is similar to that used for a previous nighttime event studied by Inan et al [1999], except the new 5-constituent model of ionosphere relaxation [Lehtinen and Inan, 2007] for better description of low altitudes (<50 km).…”

Section: Discussionmentioning

confidence: 99%

Massive disturbance of the daytime lower ionosphere by the giant γ‐ray flare from magnetar SGR 1806–20

Inan

Lehtinen

Moore

et al. 2007

Geophysical Research Letters

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The giant γ‐ray flare from SGR 1806‐20 created a massive disturbance in the daytime lower ionosphere, as evidenced by unusually large changes in amplitude/phase of subionospherically propagating VLF signals. The perturbations of the 21.4 kHz NPM (Lualualei, Hawaii) signal observed at PA (Palmer Station, Antarctica) correspond to electron densities increasing by a factor of ∼100 to ∼103 cm−3 at ∼60 km and ≳1000 to ∼10 cm−3 at ∼30 km altitude. Enhanced conductivity produced by flare onset endured for >1 hour, the time scale determined by mutual neutralization. A brief (∼100 ms) low frequency (∼3 to 6 kHz) emission is also observed during the flare onset.

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“…No GJs were recorded by ISUAL along the NPM-Suva path within 200 km off the TRGCP during the period of VLF observations presented in this study. Lehtinen and Inan (2007) proposed a new chemistry model for the stratosphere/lower ionosphere, and attributed long recoveries (∼10 3 to 10 4 s) of early/fast events to the persistent ionization generated by gigantic jet discharges at low altitude. The recent observations of a GJ-followed sprite by van der , and associated strong early/fast VLF amplitude perturbations (>1 dB) observed concurrently with a GJ, confirm the production of large electron density enhancements in the D-region of the ionosphere due to GJs.…”

Section: Unusually Long Recovery Early/fast Eventsmentioning

confidence: 99%

Lightning-associated VLF perturbations observed at low latitude: Occurrence and scattering characteristics

Kumar

2013

Earth Planet Sp

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The occurrence of short-timescale (∼1-100 s) perturbations (early VLF events) on four Very Low Frequency (VLF) transmitter signals (call signs: NWC, NPM, VTX, NLK), recorded at Suva (18.1• S, 178.5• E, L = 1.16), shows the most frequent occurrence on the NWC signal and least on the VTX. Daytime early/fast events on the NWC transmission are (0.2-0.5 dB) with only negative amplitude perturbations with comparatively lower recovery times (10-30 s) as compared with most nighttime events with amplitude perturbations of 0.2-1.5 dB and recovery times of 20-80 s. The World-Wide Lightning Location Network detected causative lightnings for 74 of 453 early VLF events out of which 54 (73%) were produced due to narrow-angle scattering, and by 20 (27%) due to wide-angle scattering. The recovery (decay) of the scattered amplitude of early/fast events on the NWC signal shows both exponential and logarithmic forms, but the linear correlation coef cient is better with a logarithm t. The rst observations of early/slow events in daylight propagation are presented. Initial results on early/fast events with unusually long recoveries (≥5 min) and strong perturbations (≥1 dB) indicate that they are mainly observed on the transmissions from NPM and NLK in the nighttime only, with rare occurrence on other transmissions. Such unusually long recovery of early/fast events may be associated with large ionic conductivity perturbations associated with gigantic jets.

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Possible persistent ionization caused by giant blue jets

Cited by 64 publications

References 23 publications

Underlying mechanisms of transient luminous events: a review

Underlying mechanisms of transient luminous events: a review

Massive disturbance of the daytime lower ionosphere by the giant γ‐ray flare from magnetar SGR 1806–20

Lightning-associated VLF perturbations observed at low latitude: Occurrence and scattering characteristics

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