Principles of Lightning Physics

by Vladilav Mazur

Overview

The quality of new lightning observations and measurements has greatly improved during the past thirty 30 years, due to newly-developed tools, technology and techniques. Significant progress has also been achieved in the physical understanding of lightning processes during this same period. This book presents and discusses the most up-to-date physical concepts that govern many lightning events in nature, as well as lightning interactions with man-made structures. The author's approach to the understanding of lightning —- ¬– to seek out, and to show what is common to all lightning flashes —-– are illustrated by an analysis of each type of lightning and the multitude of lightning-related features. Using this approach, the book examines the work that has gone into the development of new physical concepts, and provides critical evaluations of the existing knowledge of the physics of lightning and the lexicon of terms and definitions used in lightning research.

Product Details

ISBN-13:	9780750311533
Publisher:	Iop Publishing Ltd
Publication date:	02/28/2017
Series:	IOP Expanding Physics
Pages:	194
Product dimensions:	7.37(w) x 10.23(h) x 0.63(d)

About the Author

Vladislav Mazur has been a Physicist at the National Severe Storms Laboratory in Norman, Oklahoma, a division of the National Oceanic and Atmospheric Administration, since 1984. His research interests include lightning physics, lightning-aircraft interactions, computer simulations of lightning processes, interaction of lightning with ground structures, and lightning protection and its physical aspects. He was a pioneer of high-speed photography of lightning in the early 1990s.

Table of Contents

Preface xi

Acknowledgements xiv

Author biography xv

1 The components of lightning 1-1

1.1 Features of lightning plasma 1-1

1.2 Lightning is more than a spark 1-2

1.2.1 Corona glow 1-2

1.2.2 Corona streamers 1-3

1.2.3 Transition from corona streamers to a positive leader 1-5

1.2.4 Transition from corona streamers to a negative leader l-6

1.3 Conditions for leader propagation 1-8

1.4 Lightning leaders in nature 1-12

References 1-15

2 Lightning leaders versus free-burning arcs 2-1

2.1 Similarities and differences 2-1

2.2 The E-I relationship, from the results of laboratory measurements and the modeling of free-burning arcs 2-2

2.3 The E-I relationship and the luminosity of leader channels 2-7

References 2-9

3 Physical concepts of a lightning leader model 3-1

3.1 The space charge leader concept based on cloud charge collection 3-1

3.2 The bi-directional, uncharged leader concept based on induced charges 3-3

3.3 Comparing the outputs of the two leader models 3-5

References 3-8

4 Verifying the concept of the bidirectional leader 4-1

4.1 How studying lightning strikes to aircraft has helped to solve the puzzle of lightning development 4-1

4.1.1 Lightning radar echo 4-2

4.2 How does an aircraft trigger lightning? 4-5

4.3 Environmental conditions that lead to aircraft-triggered lightning 4-9

4.3.1 Hypothesis of a natural lightning-triggering mechanism in thunderstorms 4-11

References 4-13

5 Defining the types of lightning 5-1

5.1 The visible features of lightning flashes 5-1

5.2 Defining the types of lightning using the bidirectional bipolar leader concept 5-7

5.2.1 Intra-cloud flashes 5-7

5.2.2 Cloud-to-ground flashes 5-11

References 5-14

6 The electrostatic theory of lightning discharges 6-1

6.1 Cloud potential and induced charges of lightning 6-1

6.2 The relationship between the electric fields produced by leaders and return strokes 6-2

6.3 The relationship between lightning processes and space charges in thunderstorms 6-4

6.3.1 Thunderstorm model 6-4

6.3.2 Development of the cloud-to-ground leader 6-6

6.3.3 Return stroke 6-11

6.3.4 Electric field changes produced by CG flashes 6-12

6.3.5 Development of the intra-cloud leader 6-13

6.4 Applications and limitations of the electrostatic model 6-14

References 6-17

7 Lightning triggered by rockets with wire and by tall structures 7-1

7.1 The idea of artificially triggered lightning 7-1

7.2 Concept and features of the classic rocket-triggered lightning technique 7-2

7.2.1 Processes related to melting of the trailing wire 7-3

7.3 Concept and features of the altitude-triggered lightning technique 7-6

7.4 Conditions required for triggering lightning with rocket-and-wire techniques 7-7

7.5 On leaders and return strokes in rocket-triggered lightning 7-8

7.6 Upward lightning triggered by tall ground structures 7-9

7.6.1 Conditions for upward lightning initiation 7-9

7.6.2 Understanding luminosity variations in the upward-lightning channel 7-12

7.7 Features of positive and negative leaders determined from studies of triggered lightning 7-15

References 7-18

8 Understanding current cutoff in lightning 8-1

8.1 Definition and manifestation of current cutoff in different lightning events 8-1

8.2 The death of the leader in unbranched lightning channels 8-2

8.3 Current cutoff in branched leaders 8-3

8.3.1 The screening effect in single and branched channels 8-3

8.3.2 The role of branch-screening in current cutoff 8-4

8.4 Arc instability and current cutoff 8-8

References 8-9

9 The phenomenon of recoil leaders 9-1

9.1 The nature of recoil and dart leaders 9-1

9.2 The relationship between recoil leaders and M-events: cause and effect 9-5

9.3 The electrostatic model of an M-event that produces an M-component 9-9

9.3.1 The electrostatic model of a dart leader-return stroke sequence in CG flashes 9-10

9.3.2 The electrostatic model of an M-event 9-12

9.4 The universal nature of M-events in lightning 9-14

References 9-15

10 The physical concept of recoil leader formation 10-1

10.1 The relationship between the internal electric field and current in lightning leaders 10-1

10.2 Current cutoff prior to the occurrence of recoil leaders 10-2

10.3 The development of recoil leaders 10-3

10.4 A proposed conceptual model of recoil leader formation 10-5

10.4.1 Recoil leader formation and polarity asymmetry in branched leaders 10-8

10.5 Conclusion 10-10

References 10-10

11 Some lightning protection issues viewed through the lens of lightning physics 11-1

11.1 Striking distance versus the parameters of downward leaders in lightning protection of ground installations 11-1

11.2 A physical model of leader interaction with a ground structure 11-4

11.3 On the hazardous effects of upward lightning to tall structures 11-8

11.4 Sharp-tipped versus blunt-tipped lightning rods 11-8

11.5 Lightning protection of aircraft 11-9

References 11-11

12 Lightning initiation-the most difficult issue of lightning physics 12-1

12.1 Hydrometeor theory of lightning initiation 12-1

12.2 The runaway theory of lightning initiation 12-4

12.3 Evidence supporting the hydrometeor theory of lightning initiation 12-5

References 12-8

Appendix A-1