Characteristics of electric fields of upward negative stepped leaders

Azadifar, Mohammad; Rachidi, Farhad; Rubinstein, Marcos; Paolone, Mario; Rakov, Vladimir A.; Pavanello, D.; Metz, Stefan; Romero, C.

doi:10.1109/sipda.2015.7339279

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…More recently, by observing the rocket-triggered lightning in the inland plateau of China or the tower-initiated lightning in different countries, some characteristics of current or electromagnetic field of the whole upward positive lightning were analyzed [e.g., Heidler et al, 2015;Liu et al, 1994]. However, the detailed information about the upward negative leader is still limited, mainly about the analysis of channel base current and electric field waveform of the leader steps but without corresponding optical images [e.g., Zhou et al, 2012;Azadifar et al, 2015]. The only one combined observation of current and optical propagation of the upward negative leader was restricted by the coarse spatial resolution [Miki et al, 2014].…”

Section: Introductionmentioning

confidence: 99%

Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage

Jiang

Qie

et al. 2017

Geophysical Research Letters

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By conducting comprehensive observation on the rarely triggered positive lightning flashes, two cases of upward negative leaders were quantitatively investigated with simultaneous data of current, optical, and electromagnetic field changes at fine time resolution. The impulsive channel current associated with the initial leader stepping involved pulse interval, peak, charge of 19.1 μs, 122.3 Å, 465.9 μC, and 20.3 μs, 58.4 Å, 267.2 μC, for the two cases, respectively. The negative charge of an individual step was nearly an order of magnitude larger than that of the positive leader step in triggered lightning. The upward negative stepped leader branches shortly after initiation, and consequently, the stepping‐caused current pulses became multipeaked, wider, and more frequent in waveforms. The main leader tip propagated at an average speed of 2.10 × 105 m/s, while its partial speed fluctuated a lot as was significantly influenced by the behaviors of subbranches development.

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Section: Introductionmentioning

confidence: 99%

Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage

Jiang

Qie

et al. 2017

Geophysical Research Letters

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“…A quantitate study of the Category A pulses of our dataset was reported in [21]. Table 1 presents the average and standard deviations of some parameters of the electric field waveforms of Category A pulses.…”

Section: Discussion On the Similarity Of Upward And Downward Negative...mentioning

confidence: 99%

“…The electric field sensor was installed on the roof of a 25-m tall building (Huber+Suhner) in Herisau, 14.7 km away from the Säntis Tower. More information on the installed electric field system can be found in [21].…”

Section: B Electric Field Measurement Stationmentioning

confidence: 99%

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On the Similarity of Electric Field Signatures of Upward and Downward Negative Leaders

Azadifar

Rubinstein

Rachidi

et al. 2018

2018 34th International Conference on Lightning Protection (ICLP)

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We report on general characteristics of simultaneous channel-base current and distant electric fields for five upward positive flashes recorded at the Säntis tower in Summer 2014. We describe the salient features of the upward negative leader process initiating upward positive flashes and compare them with those of the downward negative leader process found in the literature. Our observations show considerable similarity between those two processes.

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Fast initial continuous current pulses versus return stroke pulses in tower‐initiated lightning

et al. 2016

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We present a study focused on pulses superimposed on the initial continuous current of upward negative discharges. The study is based on experimental data consisting of correlated lightning current waveforms recorded at the instrumented Säntis Tower in Switzerland and electric fields recorded at a distance of 14.7 km from the tower. Two different types of pulses superimposed on the initial continuous current were identified: (1) M‐component‐type pulses, for which the microsecond‐scale electric field pulse occurs significantly earlier than the onset of the current pulse, and (2) fast pulses, for which the onset of the field matches that of the current pulse. We analyze the currents and fields associated with these fast pulses (return‐stroke type (RS‐type) initial continuous current (ICC) pulses) and compare their characteristics with those of return strokes. A total of nine flashes containing 44 RS‐type ICC pulses and 24 return strokes were analyzed. The median current peaks associated with RS‐type ICC pulses and return strokes are, respectively, 3.4 kA and 8 kA. The associated median E‐field peaks normalized to 100 km are 1.5 V/m and 4.4 V/m, respectively. On the other hand, the electric field peaks versus current peaks for the two data sets (RS‐type ICC pulses and return strokes) are characterized by very similar linear regression slopes, namely, 3.67 V/(m kA) for the ICC pulses and 3.77 V/(m kA) for the return strokes. Assuming the field‐current relation based on the transmission line model, we estimated the apparent speed of both the RS‐type ICC pulses and return strokes to be about 1.4 × 108 m/s. A strong linear correlation is observed between the E‐field risetime and the current risetime for the ICC pulses, similar to the relation observed between the E‐field risetime and current risetime for return strokes. The similarity of the RS‐type ICC pulses with return strokes suggests that these pulses are associated with the mixed mode of charge transfer to ground.

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Characteristics of electric fields of upward negative stepped leaders

Cited by 5 publications

References 10 publications

Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage

Upward negative leaders in positive triggered lightning: Stepping and branching in the initial stage

On the Similarity of Electric Field Signatures of Upward and Downward Negative Leaders

Fast initial continuous current pulses versus return stroke pulses in tower‐initiated lightning

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