Electrodynamic and thermodybamic modeling of the lightning channel
Abstract/Contents
- Abstract
- Lightning is a form of of an electric breakdown of air caused by the strong electric field that is induced by charge accumulation in the cloud during a thunderstorm. During lightning, a current of tens of thousands of amperes flows in the lightning channel and a charge of several coulombs is transfered between different parts of the cloud or between the cloud and the ground. These high-current and high-energy phenomena cause various effects that influence our daily life and the Earth's electromagnetic environment, including near-Earth space. For this reason it is of great interest to improve our understanding of the characteristics of the lightning channel and the fundamental physics underlying the development of lightning. Lightning consists of physical processes that span a wide range of spatial and temporal scales. Despite decades of research, many questions concerning the fundamental physics of lightning remain unanswered. This lack of understanding is caused by a combination of factors including the difficulty in obtaining high-quality experimental data and the intrinsic complexity in the physical processes involved. In this work, a numerical model is constructed to handle the electrodynamics and the thermodynamics of the lightning channel as well as the complex geometrical structure of the lightning channel. This model is applied to investigate three lightning processes: the subsequent return stroke, the leader step and the large scale geometrical structure of the lightning channel. The study of the subsequent return stroke reveals that the current and optical waves may propagate along the channel at significantly different speeds. This result has a profound impact on the calculated return stroke electromagnetic radiation, which in turn affects many aspects of lightning-related studies, including lightning geolocation and lightning-upper-atmosphere coupling. The model also predicts a finite time delay between the return stroke current and optical wavefront. The leader-step study focuses on reproducing the ground-station recordings of the electric field pulse associated with single leader steps. It is demonstrated that a parsimonious model is sufficient to capture the observed characteristics of the waveforms. In the study of the large-scale structure of the lightning channel, a probabilistic model is used to determine the growth and branching of the lightning channel. The model is then applied in a Monte-Carlo type algorithm to determine the probability distribution of the lightning strike locations on the ground given the location of the initial channel in the cloud. The protection efficiency of a metallic rod on the ground is investigated by comparing the estimated probability distributions using simulations that are with or without the metallic rod present on the ground.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2014 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Liang, Can |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering |
| Primary advisor | Inan, Umran S |
| Thesis advisor | Inan, Umran S |
| Thesis advisor | Close, Sigrid, 1971- |
| Thesis advisor | Lehtinen, Nikolai G |
| Advisor | Close, Sigrid, 1971- |
| Advisor | Lehtinen, Nikolai G |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Can Liang. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2014. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2014 by Can Liang
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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