An Introduction to Lightning, Vernon Cooray, Springer, 2015. $79.99 (386 pp.). ISBN 978-94-017-8937-0 Buy at Amazon
Lightning is a phenomenon with important consequences for humankind. It kills hundreds of people around the world each year and causes billions of dollars in damage. The present understanding of lightning is based on more than 200 years of detailed research and observation since the time of Benjamin Franklin, and contributions to the field are growing rapidly.
An Introduction to Lightning gives a solid overview and emphasizes the contributions of the author, Vernon Cooray, who has studied the physics of lightning for more than three decades. The book takes a physics-based approach: In a clear and digestible manner, it provides detailed information about the physical processes involved in the lightning discharge and discusses the pertinent principles of lightning protection from the perspective of a general reader. The author’s intention is to convey information at the introductory level, and in that he is successful. However, the text is by no means comprehensive, and its reference list is moderate at best. Nevertheless, Cooray’s text is a good primer for understanding the more detailed and well-documented work presented in other books, such as Vladimir Rakov and Martin Uman’s Lightning: Physics and Effects (Cambridge University Press, 2003).
Each of the 20 chapters of An Introduction to Lightning starts with what is effectively an introduction, closes with a brief list of references, and presents in between an appropriate amount of detailed figures, illustrative cartoons, and interesting photographs. The language used throughout the book is easy to understand. The chapter ordering is natural and intuitive.
Chapter 1 offers an abbreviated history of early considerations of lightning and culminates with Benjamin Franklin’s seminal contributions. Chapter 2, which tackles the topic of discharge physics, describes electron avalanche, streamer discharges, corona discharges, and leader discharges. The next chapter provides the mathematical framework for the electromagnetics discussed throughout the book and illustrates the strength of that framework through its application to the electric fields produced by several different components of the lightning flash. Earth’s atmosphere and its electrical properties are discussed in chapter 4; the two chapters following it offer a brief overview of the physical processes involved in thundercloud formation and charging.
After background chapters 1 through 6, the author investigates the basic requirements for lightning-flash initiation in chapter 7 and describes in detail the mechanisms involved. Chapter 8 progresses to discuss the various types of currents that occur during a lightning flash and presents experimental observations of those current components. In chapter 9, the resulting electric fields are interpreted in terms of the discharge physics introduced in chapter 2. Two types of lightning return-stroke models are then investigated in chapter 10, and chapter 11 compares measurements of the optical lightning return-stroke speed with results obtained from theoretical modeling. Chapter 12 develops the mathematics necessary to incorporate the effects of a finitely conducting Earth into the theory.
Chapters 13–18 address some practical considerations for localized effects of lightning: geolocation methods (determining where the lightning strike occurred), electrostatic cloud potential and its use in identifying structures susceptible to lightning strikes, the infrastructural damage produced by such strikes, the impact of lightning on the human body and psyche, and how to protect home and property.
The far-reaching effects of lightning are considered in chapter 19, and chapter 20 goes on to describe unusual forms of lightning. For example, the author briefly touches on the excitation of the Schumann resonances by lightning flashes, on such effects as the production of sprites, elves, and gigantic jets in the ionosphere, and on how lightning generates energetic radiation—for example, terrestrial gamma-ray flashes. None of the effects in chapter 19 are discussed in great detail, and referencing in those final two chapters is not satisfying.
Overall, An Introduction to Lightning is worthy of an introductory lightning-physics course. Its primary drawback is its cursory treatment of citations, which forces readers interested in greater detail to fend for themselves. As a classroom textbook, an additional drawback is a lack of example problems in the text and the omission of end-of-chapter problems. Nevertheless, the book is clear and easy to digest, and it enables a student to obtain a solid understanding of the physical processes involved in the lightning discharge.
Robert Moore is an associate professor in the department of electrical and computer engineering at the University of Florida in Gainesville. He conducts research in the lightning and ionospheric radio labs there and is currently secretary of the American Geophysical Union’s Atmospheric and Space Electricity focus group.
