A model of preliminary breakdown pulse peak currents and their relation to the observed electric field pulses

Kašpar, Petr; Santolı́k, O.; Kolmašová, Ivana; Farges, Thomas

doi:10.1002/2016gl071483

Cited by 10 publications

(17 citation statements)

References 38 publications

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“…Tables show the overall ranges of the IBP parameters for the three flash initiations studied. The IBP peak current range of 0.7 to 165 kA is similar to the 3–100 kA range reported by Betz et al (), the 24–154 kA of Karunarathne et al (), the 9–64 kA of Kolmašová et al (), and the 20–189 kA of Kašpar et al (). Our range of current propagation velocities, total charge, and charge moments also approximately agree with the high‐end values but extend lower values than those found by Karunarathne et al ().…”

Section: Discussionsupporting

confidence: 86%

“…In most previous IBP modeling studies (e.g., da Silva & Pasko, ; Karunarathne et al, ; Kašpar et al, ; Nag & Rakov, ; Nag & Rakov, ; Shao & Heavner, ), IBPs have been modeled using smooth IBP current waveforms that produce smooth bipolar pulses without any of the subpulses commonly detected on the leading side of the waveform (e. g., Weidman & Krider, ; Stolzenburg et al, ). To be able to include subpulses, we determine the IBP current waveform I ( t ) from the IBP E‐change measurements.…”

Section: Overview Of Ibp Modelingmentioning

confidence: 99%

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Studying Sequences of Initial Breakdown Pulses in Cloud‐to‐Ground Lightning Flashes

et al. 2020

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The properties of the first 5–12 classic initial breakdown pulses (IBPs) of three cloud‐to‐ground (CG) lightning flashes were determined using a modified transmission line model. As part of the modeling, the current with respect to time of each IBP was determined from the measured electric field changes at multiple sites using three theoretical methods called Hilbert transform, Hertzian dipole, and matrix inversion. In the transmission line modeling the length of each IBP was estimated from high‐speed video data of the IBPs. The modeling provided the following properties of the larger classic IBPs in each flash: peak current, velocity, total charge, charge moment, radiated power, and total energy dissipated for successive IB pulses in three developing lightning flashes. For the main initial leader channel in the three CG flashes (and for one long branch), IBP peak current was largest for the first or second classic IBP and declined mostly monotonically with successive IBPs. For the same channels, IBP current velocity was smallest for the first classic IBP and increased mostly monotonically with successive IBPs. The smallest velocities were (2.0, 2.5, 2.5, 3.0) × 107 m/s, respectively, while the largest velocities were (9.2, 12.2, 11.5, 12.0) × 107 m/s, respectively. These data support earlier hypotheses that it is the classic IB pulses during initial leader of normal negative CG flashes that change the nonconductive air into an ionized path that is sufficiently long and conductive to start the stepped leader.

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Section: Discussionsupporting

confidence: 86%

Section: Overview Of Ibp Modelingmentioning

confidence: 99%

Studying Sequences of Initial Breakdown Pulses in Cloud‐to‐Ground Lightning Flashes

et al. 2020

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“…Kašpar et al (2017) concluded that IBP peak currents can reach as high as 200 kA, comparable to or higher than the following return stroke peak currents. Thus, the modeling of Kašpar et al (2017) is consistent with the observational finding of Brook (1992) that some wintertime CG flashes had IB pulses with peak E-change amplitudes greater than or equal to the following return stroke peak Echange amplitude. Nag and Rakov (2016) used MTLE and MTLL transmission line models to simulate a CG flash from initiation through the first return stroke.…”

Section: Introductionmentioning

confidence: 97%

“…Using their computational model, da Silva and Pasko (2015) were able to match an IBP modeled in Karunarathne et al (2014) and an NBP modeled by Eack (2004) and Watson and Marshall (2007). More recently, this method was extended by Kašpar et al (2017) to model the peak currents of distant IBPs. Kašpar et al (2017) concluded that IBP peak currents can reach as high as 200 kA, comparable to or higher than the following return stroke peak currents.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, this method was extended by Kašpar et al (2017) to model the peak currents of distant IBPs. Kašpar et al (2017) concluded that IBP peak currents can reach as high as 200 kA, comparable to or higher than the following return stroke peak currents. Thus, the modeling of Kašpar et al (2017) is consistent with the observational finding of Brook (1992) that some wintertime CG flashes had IB pulses with peak E-change amplitudes greater than or equal to the following return stroke peak Echange amplitude.…”

Section: Introductionmentioning

confidence: 99%

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Modeling Initial Breakdown Pulses of Lightning Flashes Using a Matrix Inversion Method

Karunarathne

Marshall

et al. 2019

Radio Science

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This study describes a new method for modeling the radiated electric field (E) of initial breakdown pulses (IBPs) of lightning flashes. Similar to some previous models, it is assumed that E pulses are caused by a current propagating along a vertical path, and an equation based on Maxwell's equations is used to determine E due to the current. A matrix inversion technique is used with the IBP radiation term of E to determine the IBP current waveform directly from far‐field E measurements rather than assuming a parameterized current waveform and searching for appropriate parameters. This technique is developed and applied to observations of six previously modeled IBPs. Compared to the prior modeling, this matrix inversion method gives significantly better results, based on calculated IBP goodness of fit to the original E data. In addition, this model can match IBP subpulses along with representing the overall bipolar IBP waveform. This method should be useful for studying IBPs because once the IBP current is known, one can calculate other physical parameters of IBPs, such as charge moment change, total charge moved, and total power radiated. Thus, the more realistic IBP current waveform determined by this technique may offer new clues about the physical mechanism causing IBPs.

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VLF Emissions With Banded Structure in the 16‐ to 39‐kHz Frequency Range Measured by a High‐Latitude Ground‐Based Receiver

Macotela

Němec

Manninen

et al. 2019

Geophysical Research Letters

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Very low frequency (VLF) emissions of natural origin were identified for the first time by analyzing 1-hr ground-based magnetic field spectrograms in the 0.2-to 39-kHz frequency range. Data were used from the Kannuslehto radio receiver (L-shell~5.5), recorded during different campaigns between 2006 and 2019. The spectrograms exhibit banded structures, which consist of several strip elements that vary in time and frequency over the event duration. Statistical analysis of 95 events shows that they are observed in the frequency range that extends from 2 to~37 kHz, and mainly appearing above 16 kHz. The events span from 4 to 110 min and occur in the evening sector (~17-01 magnetic local time), mostly during quiet geomagnetic conditions. Furthermore, they are primarily left-handed polarized and are associated with bursts of lightning-related radio emissions such as sferics and tweeks.Plain Language Summary Advances in modern technology have created tangible scientific and societal benefits, allowing us to make new discoveries, perform better observations, and monitor important parameters of our Earth's condition. In this study, new digital processing tools are used to uncover a natural, namely, non-man-made, very low frequency (VLF) radio wave emission never observed before. These emissions consist of several strips as appear on our detector screens, with structures having frequency drifts that vary during the event duration. Moreover, the range of frequencies in which these emissions are observed, 16-39 kHz, is higher than the typical one used for VLF observations. The measurements were made in Northern Finland during different campaigns, between 2006 and 2019, using~10-m size square-loop radio antennas installed on the ground. The duration of the structured emissions ranges from about four to a hundred minutes. These emissions occur during evening and early night hours, and when the Earth's magnetic conditions are calm. Additionally, we learned that the field perpendicular to the wave propagation rotates clockwise when looking at the incoming wave. A remarkable characteristic of these emissions is that they are coincidental in time with the occurrence of bursts of lightning VLF emissions.

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A model of preliminary breakdown pulse peak currents and their relation to the observed electric field pulses

Cited by 10 publications

References 38 publications

Studying Sequences of Initial Breakdown Pulses in Cloud‐to‐Ground Lightning Flashes

Studying Sequences of Initial Breakdown Pulses in Cloud‐to‐Ground Lightning Flashes

Modeling Initial Breakdown Pulses of Lightning Flashes Using a Matrix Inversion Method

VLF Emissions With Banded Structure in the 16‐ to 39‐kHz Frequency Range Measured by a High‐Latitude Ground‐Based Receiver

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