Modeling of the Stepping Process of Negative Lightning Stepped Leaders

Cooray, Vernon; Arévalo, Liliana

doi:10.20944/preprints201708.0077.v1

Cited by 5 publications

(1 citation statement)

References 15 publications

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“…Nag and Rakov () simulated both the preliminary breakdown pulses and leader steps using a TL‐type model. Cooray and Arevalo (), using a one‐dimensional model of stepped leader development considering the processes in its streamer zone, estimated the step length, step formation time, and propagation speed of stepped leaders as a function of the prospective return stroke peak current. Zhang et al () presented a one‐dimensional modeling study of the dynamics of branching of negative downward lightning leaders.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Stepping and Branching Processes in Negative Lightning Leaders

et al. 2020

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A numerical model with physical timing and grid spacing of 3 m is applied to studying the progression (including stepping and branching) of negative lightning stepped leader. The asymmetry between positive and negative streamers is taken into account via using polarity‐dependent initiation and propagation field thresholds. The stepped nature of negative leader is confirmed to be caused by this asymmetry. The step formation process of the negative leader is modeled to begin with the appearance of space stems inside and in the immediate vicinity of its streamer zone (corona streamer burst completing the preceding step). Some of those space stems evolve into space leaders, which can connect to the primary leader channel, thereby facilitating its extension. Model‐predicted morphology and dynamics of negative leaders are in good agreement with the recent recordings of lightning stepped and dart‐stepped leaders obtained using high‐speed video cameras, and their electrical parameters are in line with the current knowledge on negative lightning leaders.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Stepping and Branching Processes in Negative Lightning Leaders

et al. 2020

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Branching Morphology of Negative Leaders with Different Propagation Directions in Natural Lightning

et al. 2022

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Comparing the branching features of negative leaders with different propagation directions could provide insight into the common tendency of development pathways and the formation pattern of branches in natural lightning. This paper reports an upward negative leader (UNL) and a downward negative leader (DNL), and their branching features are analyzed and compared. The UNL is classified into vertical (UNL-V) and horizontal (UNL-H) segments based on propagation directions at different stages. The downward negative leader (DNL) is classified into main (DNL-M) and secondary (DNL-S) channels based on whether the channel is ultimately connected to the upward connecting leader. The vital angle parameters characterizing the branching morphology are investigated. For the strong branch eventually forming a section of the main channel, its deflection angle conforms to the lognormal distribution with a mean range of 22–36°. The included angle between the branches and the deflection angle of weak branches conform to the normal distribution with means close to 40° and 60°, respectively. Moreover, the velocity for four categories of negative leaders decreases noticeably by two or more branching behaviors in a frame interval of about 80 μs. In particular, similarities in branching morphology have been found in UNL-H, UNL-V, and DNL-S, with a semblable distribution in deflection and included angles. Statistical results indicate that branches of DNL-M tend to follow the previous direction of leader development, and the branching behavior has minimal impact on its velocity.

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Origin of the Fine Scale Tortuosity in Sparks and Lightning Channels

Cooray

2018

Atmosphere

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Abstract:The physical reason for the small-scale tortuosity observed in sparks and lightning channels is unknown at present. In this paper, it is suggested that the small-scale tortuosity of the discharge channels is caused by the natural tendency for subsequent leader streamer bursts to avoid each other but at the same time to align as much as possible along the direction of the background electric field. This process will give rise to a discharge channel that re-orients in space during each streamer burst creating the small scale tortuosity.

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Modeling of the Stepping Process of Negative Lightning Stepped Leaders

Abstract: Abstract-

Cited by 5 publications

References 15 publications

Numerical Simulation of Stepping and Branching Processes in Negative Lightning Leaders

Numerical Simulation of Stepping and Branching Processes in Negative Lightning Leaders

Branching Morphology of Negative Leaders with Different Propagation Directions in Natural Lightning

Origin of the Fine Scale Tortuosity in Sparks and Lightning Channels

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