Inferences on upward leader characteristics from measured currents

Nag, A.; Cummins, Kenneth L.; Plaisir, M. N.; Wilson, Jennifer G.; Crawford, David; Brown, Robert G.; Noggle, R. Carl; Rassoul, H. K.

doi:10.1016/j.atmosres.2020.105420

Cited by 6 publications

(15 citation statements)

References 23 publications

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“…This strongly suggests that the current pulses present in upward leaders are induced by the electric field change produced by the steps in the propagation of the negative downward leader. Similar time intervals between the current pulses for UUL from a 91.5 m tall tower (Nag et al, 2021) are also shown in Table 3 for Table 3 also shows the current amplitude for leader pulses. In both leaders the amplitude of the pulses gets higher during the approach of the downward leader to the upward leaders (Figure 8b).…”

Section: Time Interval and Amplitude Of Electric Field Changes And Cu...mentioning

confidence: 53%

“…This strongly suggests that the current pulses present in upward leaders are induced by the electric field change produced by the steps in the propagation of the negative downward leader. Similar time intervals between the current pulses for UUL from a 91.5 m tall tower (Nag et al, 2021) are also shown in Table 3 for comparison. The time intervals between the current pulses from a 7 m tall structure observed by Schoene et al (2008) (12 to 21 μs), and from a 60 m tall tower on top of a hill observed by (30 to 50 μs) are also close to the average interstep time found in this work.…”

Section: Time Interval and Amplitude Of Electric Field Changes And Cu...mentioning

confidence: 91%

“…The reversed current of leader A (UUL) reaches a minimum of -701 A. This backflow current was modelled by Becerra and Cooray (2009) and measured by Schoene et al (2008), Visacro et al (2010), andNag et al (2021) for structures with different heights (Table 2).…”

Section: Backflow Currentmentioning

confidence: 99%

“…This can be explained by the fact that in our study the downward leader that induced the upward leaders occurred overhead the instrumented lightning rods and produced a -73 kA peak current return stroke. In Nag et al (2021), the downward leaders produced return strokes with peak currents ranging from -13 to -69.3 kA but at larger distances (185 to 783 m) from the instrumented tower.…”

Section: Time Interval and Amplitude Of Electric Field Changes And Cu...mentioning

confidence: 99%

“…Although a few current measurements of upward leaders have been reported from tall towers higher than 60 m (e.g. Saba et al, 2015;Visacro et al, 2017;Arcanjo et al, 2019;Nag et al, 2021 for towers over mountains), from buildings (Saba et al, 2017), and from small structures (Schoene et al, 2008, vertical conductor of 7 m height), no current measurements of upward connecting leaders from common residential buildings have been reported in the literature. Moreover, no study has ever been done on upward leaders competing to connect a downward leader.…”

Section: Introductionmentioning

confidence: 99%

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Upward leaders from instrumented lightning rods competing to connect a downward leader during a lightning attachment process

Saba

Lauria

Schumann³

et al. 2022

Preprint

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In this paper we analyze electric-field and current measurements of competing upward leaders induced by a downward negative lightning flash that struck a residential building. The attachment process was recorded by two high-speed cameras running at 37,800 and 70,000 images per second and the current measured in two lightning rods. Differently from previous works, here we show, for the first time, the behavior of multiple upward leaders that after initiation compete to connect the negative downward moving leader. At the beginning of the propagation of the leaders that initiate on the instrumented lightning rods, current pulses appear superimposed to a steadily increasing DC current. The upward leader current pulses increase with the approach of the downward leader and are not synchronized but present an alternating pattern. All leader speeds are constant. The upward leaders are slower than the downward leader speed. The average time interval between current pulses in upward leaders is close to the interstep time interval found by optical or electric field sensors for negative cloud-to-ground stepped leaders. The upward leaders respond to different downward propagating branches and, as the branches alternate in propagation and intensity, so do the leaders accordingly. Right before the attachment process the alternating pattern of the leaders ceases, all downward leader branches intensify, and consequently upward leaders synchronize and pulse together. The average linear densities for upward leaders (49 and 82 μC/m) were obtained for the first time for natural lightning.

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Section: Time Interval and Amplitude Of Electric Field Changes And Cu...mentioning

confidence: 53%

“…This strongly suggests that the current pulses present in upward leaders are induced by the electric field change produced by the steps in the propagation of the negative downward leader. Similar time intervals between the current pulses for UUL from a 91.5 m tall tower (Nag et al, 2021) are also shown in Table 3 for comparison. The time intervals between the current pulses from a 7 m tall structure observed by Schoene et al (2008) (12 to 21 μs), and from a 60 m tall tower on top of a hill observed by (30 to 50 μs) are also close to the average interstep time found in this work.…”

Section: Time Interval and Amplitude Of Electric Field Changes And Cu...mentioning

confidence: 91%

Section: Backflow Currentmentioning

confidence: 99%

Section: Time Interval and Amplitude Of Electric Field Changes And Cu...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Upward leaders from instrumented lightning rods competing to connect a downward leader during a lightning attachment process

Saba

Lauria

Schumann³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

Measuring low-current discharges from grounded rods under high background electric fields

Arcanjo

Montanyà

Urbani

et al. 2023

Electric Power Systems Research

View full text Add to dashboard Cite

Upward Leaders Initiated From Instrumented Lightning Rods During the Approach of a Downward Leader in a Cloud‐To‐Ground Flash

et al. 2023

View full text Add to dashboard Cite

In this paper we analyze electric‐field and current measurements of upward leaders induced by a downward negative lightning flash that struck a residential building. The attachment process was recorded by two high‐speed cameras running at 37,800 and 70,000 images per second and the current measured in two lightning rods. Differently from previous works, here we show, for the first time, current measurements of multiple upward leaders that after initiation propagate to connect the negative downward moving leader. At the beginning of the propagation of the leaders that initiate on the instrumented lightning rods, current pulses appear superimposed to a steadily increasing DC current. The upward leader current pulses increase with the approach of the downward leader and are not synchronized but present an alternating pattern. All 2D leader speeds are approximately constant. The upward leaders are slower than the downward leader speed. The average time interval between current pulses in upward leaders is close to the interstep time interval found by optical or electric field sensors for negative cloud‐to‐ground stepped leaders. The upward leaders respond to different downward propagating branches and, as the branches alternate in propagation and intensity, so do the leaders accordingly. Right before the attachment process the alternating pattern of the leaders ceases, all downward leader branches intensify, and consequently upward leaders synchronize and pulse together. The average linear densities for upward leaders (49 and 82 μC/m) were obtained for the first time for natural lightning.

show abstract

Inferences on upward leader characteristics from measured currents

Cited by 6 publications

References 23 publications

Upward leaders from instrumented lightning rods competing to connect a downward leader during a lightning attachment process

Upward leaders from instrumented lightning rods competing to connect a downward leader during a lightning attachment process

Measuring low-current discharges from grounded rods under high background electric fields

Upward Leaders Initiated From Instrumented Lightning Rods During the Approach of a Downward Leader in a Cloud‐To‐Ground Flash

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