Electric and Magnetic Fields Predicted by Different Electromagnetic Models of the Lightning Return Stroke Versus Measured Fields

Baba, Yoshihiro; Rakov, Vladimir A.

doi:10.1109/temc.2009.2019122

Cited by 39 publications

(26 citation statements)

References 28 publications

(33 reference statements)

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“…Electric field waveshapes from return strokes measured at 1 to 200 km are presented in [37] and classified in [38]. Electric and magnetic field waveshapes generated by leader and return stroke, measured at close distance, can be found in [39][40][41].…”

Section: Electric Field E(t)mentioning

confidence: 99%

On the Influence of Channel Tortuosity on Electric Fields Generated by Lightning Return Strokes at Close Distance

Petrarca¹,

Minucci²,

Andreotti³

2017

PIER B

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Abstract-In this paper the results of the estimated electric field associated with tortuous lightning paths at close distance (50 m to 500 m) are shown. Such results are compared with experimental data available in the literature and are illustrated along with a quantitative analysis of the field waveforms and their frequency spectra. The limits of the usual straight-vertical channel assumption and the influence of tortuosity at different azimuth and distances from the lightning channel base are also highlighted.

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Section: Electric Field E(t)mentioning

confidence: 99%

On the Influence of Channel Tortuosity on Electric Fields Generated by Lightning Return Strokes at Close Distance

Petrarca¹,

Minucci²,

Andreotti³

2017

PIER B

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“…The main conclusion of [9] was that the two representations with distributed series inductance and fictitious dielectric coating were able to reproduce the maximum number of characteristic features of measured electromagnetic field waveforms. Furthermore, they showed that modifications of these two representations including a height-dependent distributed resistance can reproduce all the experimentally observed features.…”

Section: Introductionmentioning

confidence: 99%

“…Baba and Rakov [9] presented a comparison between available representations of the return-stroke in electromagnetic models which included:…”

Section: Introductionmentioning

confidence: 99%

“…In the analysis presented in [9], the two-dimensional FDTD technique was used to simulate the predictions of the considered electromagnetic models. The main conclusion of [9] was that the two representations with distributed series inductance and fictitious dielectric coating were able to reproduce the maximum number of characteristic features of measured electromagnetic field waveforms.…”

Section: Introductionmentioning

confidence: 99%

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On Practical Implementation of Electromagnetic Models of Lightning Return-Strokes

2016

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Abstract:In electromagnetic models, the return-stroke channel is represented as an antenna excited at its base by either a voltage or a current source. To adjust the speed of the current pulse propagating in the channel to available optical observations, different representations for the return-stroke channel have been proposed in the literature using different techniques to artificially reduce the propagation speed of the current pulse to values consistent with observations. In this paper, we present an analysis of the available electromagnetic models in terms of their practical implementation. Criteria used for the analysis are the ease of implementation of the models, the numerical accuracy and the needed computer resources, as well as their ability to reproduce a desired value for the speed of the return stroke current pulse. Using the CST-MWS software, which is based on the time-domain finite-integration technique, different electromagnetic models were analyzed, namely (A) a wire embedded in a fictitious half-space dielectric medium (other than air), (B) a wire embedded in a fictitious coating with permittivity (ε r ) and permeability (µ r ), and (C) a wire in free-space loaded by distributed series inductance and resistance. It is shown that, by adjusting the parameters of each model, it is possible to reproduce a desired value for the speed of the current pulse. For each of the considered models, we determined the values for the adjustable parameters that allow obtaining the desired value of the return speed. Model A is the least expensive in terms of computing resources. However, it requires two simulation runs to obtain the electromagnetic fields. A variant of Model B that includes a fictitious dielectric/ferromagnetic coating is found to be more efficient to control the current speed along the channel than using only a dielectric coating. On the other hand, this model requires an increased number of mesh cells, resulting in higher memory and computational time. The presence of an inhomogeneous medium generates, in addition, unphysical fluctuations on the resulting current distributions. These fluctuations, which strongly depend on the size of the coating as well as on its electric and magnetic properties, can be attenuated by considering conductive losses in the coating. Considering the efficiency in terms of the required computer resources and ease of implementation, we recommend the use of Model C (wire loaded by distributed inductance and resistance).

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“…The adequacy of this assumption is discussed in the paper, making reference to experimental data and recent theoretical investigations (e.g., (3) (4)) . In contrast with electromagnetic models (5) for which electromagnetic fields are computed simultaneously with the distribution of the current along the radiating structure (strike object and lightning channel), the use of engineering models requires the evaluation of the associated electromagnetic fields. The calculation procedure essentially depends on the ground electromagnetic properties.…”

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confidence: 99%

Extended Summaries

2012

IEEJ Trans. PE

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The demand for both data quality and the range of Cloud-toGround (CG) lightning parameters is highest for forensic applications within the electric utility industry. For years, the research and operational communities within this industry in Japan have pointed out a limitation of these LLS networks in the detection and location of damaging (high-current and/or large charge transfer) lightning flashes during the winter months (so-called "Winter Lightning"). Most of these flashes appear to be upward-connecting discharges, frequently referred to as "Ground-to-Cloud" (GC) flashes.The basic architecture and design of Vaisala's new LS700x lightning sensor was developed in-part to improve detection of these unusual and complex flashes. This paper presents our progress-to-date on this effort. We include a review of the winter lightning detection problem, an overview of the LS700x architecture, a discussion of how this architecture was exploited to evaluate and improve performance for winter lightning, and a presentation of results-to-date on performance improvement following upgrades to the instrumentation.During a 3+ week evaluation period following the upgrade, the LS network detected more than twice the number of CG strokes as the older IMPACT network (1,675 vs. 797). It also reported 594 cloud pulses. Most of the lightning was either near the west coast (Sea-of-Japan) or hundreds of km into the north-western Pacific. During the 2010 summer when lightning occurred within the interior of the network, the IMPACT LLS actually performed better than the LS network. We have recently confirmed that this limitation was rectified in July 2011 after increasing the gain of the LS sensor (due to the longer baseline distances), and installing formal released software (v1.6) in the sensors.During this first evaluation period, six high-current strokes that exhibited poor detection by the older IMPACT LLS were correlated with LEMP data from the four recording systems co-located with LS sensors. A detailed analysis for the individual sensor reports for both networks demonstrated a major improvement in the detection of these high-current lightning discharges. Although the older IMPACT network located four of the six high-current strokes, only 33% of the possible 54 sensor reports were produced by this network. Real-time operation of the LS network produced locations Table 1. November-December case summary for all six high-current strokes, although two of these strokes were poorly located. 97% of the possible 36 sensor reports were produced by this network. Algorithm refinements based in the analysis of these data, were implemented in a "reprocessed" dataset and resulted good location for all six high-current strokes, and 100% reporting by all sensors.During the second evaluation period in November-December 2010, 27 high-current (>65 kA) cases were evaluated, 20 of which were classified as GC based on LEMP waveform analysis. The lobe data for these events were not reprocessed with the improved processing algorithm. Almost all LS sensor...

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Electric and Magnetic Fields Predicted by Different Electromagnetic Models of the Lightning Return Stroke Versus Measured Fields

Cited by 39 publications

References 28 publications

On the Influence of Channel Tortuosity on Electric Fields Generated by Lightning Return Strokes at Close Distance

On the Influence of Channel Tortuosity on Electric Fields Generated by Lightning Return Strokes at Close Distance

On Practical Implementation of Electromagnetic Models of Lightning Return-Strokes

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