Two successive bidirectional leaders propagated in triggered lightning channel

Wang, Junlin; Li, Quanxin; Wang, Jianguo; Li, Cai; Su, Rui; Zhou, Mi; Fan, Yadong

doi:10.1038/s41598-022-12522-9

Cited by 4 publications

(3 citation statements)

References 23 publications

(42 reference statements)

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“…Two types of high-speed cameras (HSCs) at the distant observation site, were adopted at different times 28 . The lightning flashes triggered before 30 June were recorded by a Phantom M310 HSC configured with a Nikon 16 mm lens, operating at a rate of 8,000 frames per second (fps).…”

Section: Methodsmentioning

confidence: 99%

Three types of bidirectional leader development in triggered lightning flashes

Wang

et al. 2023

Sci Rep

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Eight cases of bidirectional leader (BL) development in artificially triggered lightning flashes are reported with synchronous high-speed camera images and electric field signals. Based on optical progressing characteristics, the eight cases can be divided into three types: a reflection type, a discontinuity type, and an inducement type. For the reflection type, the tail of a dart leader may begin to extend backward when the leader’s head reaches a branch point, or the top of the exploded triggering wire. For the discontinuity type, the initiation of a bidirectional leader below a decayed attempted leader may occur more than once preceding one return stroke. For the inducement type, the approach of another leader with the same polarity will turn a dart leader into a bidirectional leader. The reflection type and inducement type are first observed here. Two cases of the discontinuity type are observed, and both are multiple-bidirectional leaders observed for the first time. For the reflection type and inducement type, there are fluctuations in the electric field related to the BL development. The dissipation of the downward leader slows down the negative increase of the electric field. Once the BL development starts, the downward negative end of the BL moves towards the ground with the E-field negatively increasing. For the discontinuity type, the close electric field result shows no fluctuations. The BL development has a much longer duration than the other two BL types.

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Section: Methodsmentioning

confidence: 99%

Three types of bidirectional leader development in triggered lightning flashes

Wang

et al. 2023

Sci Rep

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“…Fundamentally, the stepped leader is formed by the movement of small charge pockets toward the ground. That is, a stepped leader is generated or formed in a thunderstorm cloud when the charge differences between the little region of positive charges near the storm's base and the larger region of negative charges in the center of the thunderstorm grow significantly [41]. Therefore, the stepped leader is started as a result of a large charge difference in the cloud.…”

Section: Stages Of Cloud-to-ground Lightningmentioning

confidence: 99%

Lightning-Induced Wildfires: An Overview

Song,

Xu,

et al. 2024

Fire

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Wildfire causes environmental, economic, and human problems or losses. This study reviewed wildfires induced by lightning strikes. This review focuses on the investigations of lightning mechanisms in the laboratory. Also, the paper aims to discuss some of the modeling studies on lightning-induced wildfires at different geographical locations using satellite-recorded lightning data and different statistical analyses. This review established that irrespective of the different models used to predict lightning wildfires, there is still a lack of understanding of the lightning-strike ignition mechanism; few experiments have been modeled to establish the dynamics of lightning-strike ignition. Therefore, further research needs to be carried out in this area to understand lightning ignition. It was ascertained from the various statistical modeling that lightning-induced wildfires are exacerbated by the abundant availability of fuel with a lower moisture content and high lightning efficiency. Moreover, because of changes in the climate and weather conditions, i.e., harsh weather and climate conditions due to anthropogenic activities, lightning-induced ignition wildfires have increased over the years, and they are expected to increase in the future if the climate and weather conditions continue to aggravate. Although various modeling studies have identified that lightning-induced wildfires have increased recently, no preventive measures have been conclusively proposed to reduce lightning-caused wildfires. Hence, this aspect of research has to be given critical attention. This review presents information that gives a profound understanding of lightning-induced wildfires, especially factors that influence lightning wildfires, and the state-of-the-art research that has been completed to understand lightning-induced wildfires.

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“…In recent years, with the advancement of lightning detection technologies, more bi‐directional leader progressions have been observed in natural extra‐cloud lightning discharges (Montanyà et al., 2015; van der Velde & Montanyà, 2013; Warner et al., 2016), classical rocket‐triggered lightning (Cai et al., 2021; Jiang et al., 2014; Qie et al., 2017; Su et al., 2023; Wang et al., 2022), and altitude‐triggered lightning (Chen et al., 2003; Lu et al., 2009). According to the previous observations, the bi‐directional leader development can be divided into two main types: One is an induced type, which originates from metallic objects such as aircraft, suspended conductors, and floating wires, finally resulting in an altitude‐triggered lightning (Chen et al., 2003; Lu et al., 2009; Mazur, 1989); The other is a spontaneous type, which occurred in a preexisting channel (Cai et al., 2021; Jiang et al., 2014; Montanyà et al., 2015; Qie et al., 2017) or beside an active lightning channel (Hare et al., 2019; Pu & Cummer, 2019; Yuan et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Evolution of the Leader Discharge in Bi‐Directional Propagation System in Altitude‐Triggered Lightning

Li,

Cao

et al. 2024

Earth and Space Science

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On 18 June 2023, comprehensive observations were conducted to an altitude‐triggered lightning flash. Upward positive leader (UPL) and downward negative leader (DNL) in a bi‐directional development system were detected simultaneously by a high‐speed camera, together with the coordinated measurements of magnetic field and very‐high‐frequency (VHF) emissions. High‐speed images reveal, for the first time, the enhancement of the UPL's propagation speed by DNL in the bi‐directional leader system. Concretely, the upward positive leader initially originates from a suspended wire tip and propagates at a two dimensional (2D) speed of 5.32 × 104 m/s, and after about 6.3 ms, its propagation speed was enhanced to 1.12 × 105 m/s when the stepped DNL started advancing at an average speed of 1.44 × 105 m/s. Additionally, based on the evolution of channel luminosity and the variations of magnetic radiation, it is found that there is a consistency in luminosity variation between the ascending channel and the descending channel in the bi‐directional leader system, and the amplitude of the magnetic field increases when the negative discharges start at the bottom wire end with intensive VHF emissions. Those facts indicate that the DNL has an effect, may be a positive one, on the UPL's development in the early stage of altitude‐triggered lightning.

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Two successive bidirectional leaders propagated in triggered lightning channel

Cited by 4 publications

References 23 publications

Three types of bidirectional leader development in triggered lightning flashes

Three types of bidirectional leader development in triggered lightning flashes

Lightning-Induced Wildfires: An Overview

Evolution of the Leader Discharge in Bi‐Directional Propagation System in Altitude‐Triggered Lightning

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