Mathematical modelling of return strokes

Cooray, Vernon

doi:10.1049/pbpo034e_ch6

Cited by 16 publications

(10 citation statements)

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“…1). The LEMP calculation, which requires the specification of the lightning return-stroke current along the channel [12,13] can be performed in either the time or the frequency domain. However, a direct solution in the time domain is sometimes preferable because it allows the handling, in a straightforward manner, of non-linear phenomena such as corona.…”

Section: Lemp Calculationmentioning

confidence: 99%

On the influence of corona on lightning-induced overvoltages

Dragan¹,

Florea²,

Nucci

et al. 2010

2010 30th International Conference on Lightning Protection (ICLP)

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Section: Lemp Calculationmentioning

confidence: 99%

On the influence of corona on lightning-induced overvoltages

Dragan¹,

Florea²,

Nucci

et al. 2010

2010 30th International Conference on Lightning Protection (ICLP)

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“…Our analysis shows that a suitable decay height constant can be expressed as λ e = (vτ 3 with λ em = 4000 m. With this modification, the effective decay height constant at channel sections close to ground is equal to vτ 3 , in agreement with (11), and for larger heights, it decreases forcing a reduction in the zero crossing time. Fig.…”

Section: Significance Of (7) In Modified Transmission Line Modelmentioning

confidence: 74%

“…This leads to the conclusion that the corona current is bipolar. This is in contrast to the current generation type models available today, all of which assume that the corona current is unipolar [11]. The equivalent corona currents of the current propagation models, however, are predicted to be bipolar [3].…”

Section: Constraints On the Corona Currentmentioning

confidence: 78%

“…Fig. 3(ii) shows the electric fields calculated at the same distance but by using the decay height constant given by (11). Note the clear flattening of the close electric fields for all values of τ 3 .…”

Section: Significance Of (7) In Modified Transmission Line Modelmentioning

confidence: 94%

“…Even though we have considered examples using MTLE and MTLL models (both are current propagation models), (7) is valid for both current generation and current propagation models. In the case of current generation models, the corona current per unit length at a given height along the return stroke channel can be expressed as [11] I c (z, t) = I co (z)e (16) where I c (z, t) is the corona current per unit length and τ (z) is the height-dependent discharge time constant. In some models, the discharge time constant is assumed not to vary with height, and in others, it is a function of height.…”

Section: Significance Of (7) In Modified Transmission Line Modelmentioning

confidence: 99%

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On the Relationship Between the Signature of Close Electric Field and the Equivalent Corona Current in Lightning Return Stroke Models

Cooray

Rakov

Rachidi

et al. 2008

IEEE Trans. Electromagn. Compat.

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Abstract-Engineering return stroke models can be categorized either as current generation (traveling current source type) models or current propagation (transmission line type) models. The current generation models are described among other parameters by a corona current distributed along the channel. Recent studies show that there is equivalence between the models of current generation and current propagation types. Due to this equivalence, any engineering return stroke model of current propagation type can be described in terms of an equivalent corona current per unit channel length. The measurements conducted within 10-500 m from triggered lightning flashes show that the electric field of subsequent return strokes at these distances flattens within 15 µs or so. In this paper, the constraints imposed by this feature on the temporal and spatial variation of the equivalent corona current are investigated. The results show that in order for the close fields to flatten within 15 µs or so, the equivalent corona current, should be bipolar and the corona current wave shape at late times should be identical to that of the longitudinal current time derivative. This is in contrast to most of the engineering models of current generation type, in which the corona current is assumed to be unipolar.Index Terms-Equivalent corona current, lightning electric field, return stroke models.

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Clustering and synchronization of lightning flashes in adjacent thunderstorm cells from lightning location networks data

2009

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[1] We analyzed sequences of lightning flashes in several thunderstorms on the basis of data from various ground-based lightning location systems. We identified patterns of clustering and synchronicity of flashes in separate thunderstorm cells, distanced by tens to hundreds of kilometers from each other. This is in-line with our early findings of lightning synchronicity based on space shuttle images (Yair et al., 2006), hinting at a possible mutual electromagnetic coupling of remote thunderstorms. We developed a theoretical model that is based on the leaky integrate-and-fire concept commonly used in models of neural activity, in order to simulate the flashing behavior of a coupled network of thunderstorm cells. In this type of network, the intensity of the electric field E i within a specific region of thunderstorm (i) grows with time until it reaches the critical breakdown value and generates a lightning flash while its electric field drops to zero, simultaneously adding a delta E to the intensity of the internal electric field in all thundercloud cells (E j,k,l . . .) that are linked to it. The value of DE is inversely proportional to the distance between the ''firing'' cell i and its neighbors j, k, l; we assumed that thunderstorm cells are not identical and occupy a grid with random spacing and organization. Several topologies of the thunderstorm network were tested with varying degrees of coupling, assuming a predetermined probability of links between active cells. The results suggest that when the group coupling in the network is higher than a certain threshold value, all thunderstorm cells will flash in a synchronized manner.

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Mathematical modelling of return strokes

Cited by 16 publications

References 0 publications

On the influence of corona on lightning-induced overvoltages

On the influence of corona on lightning-induced overvoltages

On the Relationship Between the Signature of Close Electric Field and the Equivalent Corona Current in Lightning Return Stroke Models

Clustering and synchronization of lightning flashes in adjacent thunderstorm cells from lightning location networks data

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