Since my days as an undergraduate engineering student, I was used to hearing comments from students that field theory is one of the most difficult subjects in the undergraduate curriculum. Later on, as a teacher, I have experienced the fact that not many teachers volunteer to teach field theory for reasons known to them. Moreover, over two decades, I have been told by my students that field theory is taught mostly from a mathematical viewpoint, and the physical understanding of issues related to field theory is normally not discussed in the classes. In this context, my own view is that it is true that nobody has seen electric field. But it exists and many physical phenomena are dependent on the nature of the electric field distribution. Therefore, it is very important to have a physical understanding of the field theory topics, so that one can correlate field theory and the associated physical phenomena. But at the same time, I am not stating that one should not learn the mathematical foundations of field theory, because field-related problem-solving requires a sound knowledge of mathematical aspects of field analysis.

I did my doctoral as well as post-doctoral works on numerical analysis of electric fields and later took up teaching electric field theory for more than one and half decades both at the undergraduate and postgraduate levels at Jadavpur University, Kolkata, India. Over the years, I have had brilliant students at both the undergraduate and postgraduate levels who have asked thought-provoking questions regarding electric field analysis. Quite a few PhD scholars have carried out outstanding works on numerical electric field analysis and electric field optimization under my supervision. They have constantly poked me to write a book on electric field analysis, emphasizing the physical understanding of field theory. Finally, in 2013, I decided to accede to the demands of my students and took up writing of this book on electric field analysis, which would not only present the mathematical aspects but also would strongly deal with the physical understanding of the basic issues of electric field theory.

This book is written with an eye on power engineering, and most of the examples that bring forth the real-life issues related to electric field analysis are from power-engineering applications in general and dielectric engineering in particular. It is to be made clear here that this book is not intended to be a book that helps in solving problems related to electric field, nor is it a book that intends to look everything from a detailed mathematical viewpoint. All the theories have been discussed in such a way that the reader gets an idea of how these theories are useful in real life. The problems given in this book are mainly intended to make the understanding of the theories clear. Wherever possible, I have tried to give objective type questions, which could be used to test whether a student has understood the finer yet practical points of electric field analysis.

This book is clearly divided into two parts. The first part, comprising Chapters 1 through 12, deals with the conventional aspects of electric field theory. These topics are not new and several other books discussing these issues are available. But I have tried to present these fundamental aspects in a way which is easily accepted by my students over the years. The second part of the book, comprising Chapters 13 through 19, concentrates on the numerical analysis and optimization of electric field. Here also, I have tried not to burden the readers with too many theoretical issues of numerical analysis. My target here is to help readers to develop their own codes after going through the chapters. Whether I have succeeded or not is left to the readers.

I thought that I should incorporate some practical case studies of numerical analysis of electric field to give readers a clear idea of how to carry out electric field analysis in a real-life case. All the examples are taken from power-engineering applications, which the students will be able to connect with their acquired knowledge. In the recent past, the optimization of engineering system has been a major area of research and the optimization of high-voltage system is no exception. Therefore, in the end, I have included a chapter on high-voltage field optimization. In this chapter, the aim is not to present optimization techniques, but the goal is to discuss how high-voltage field optimization studies are carried out by researchers. To highlight the evolution of such optimization studies, classical as well as soft computing-based optimization studies have been presented in the concerned chapter.

Over the years, I have developed a software package called TWIN, which is based on surface charge simulation method for electric field analysis and is copyrighted in my name. TWIN does not have a user-friendly graphical user interface, but is very easy to use in conjunction with simple help files that are written by me. I proposed to the publisher that this software package may be given to the purchasers of this book as a downloadable code. The publisher agreed to this request and hence I am offering TWIN^© in tandem with this book.

I would like to emphasize here that this book is neither intended for the only few who are at the very top of any group, which studies electric field theory, nor is it intended to be a made easy book. I have tried to write in such a way that this book is useful for a majority of students.

I am thankful to many who have helped me to prepare this manuscript in different ways. I cannot name them all, as I will definitely miss some of them. But I will be failing in my duties if I do not mention Dr. Biswendu Chatterjee, because without his support this book could not have been completed. I would also like to mention Dr. Kesab Bhattacharya, Dr. Abhijit Lahiri, Mr. Sandip Saha Chowdhury and Mr. Arijit Baral for their valuable inputs and help.

I am indebted to Prof. Hans Steinbigler of Technical University of Munich in so many ways starting from my post-doctoral days in the university at Munich in the mid-1990s. I thought it to be an honour to request him to write the foreword of this book and express my heartfelt thanks to him for agreeing to write the foreword.

Finally, I would like to express my gratitude to my family members, particularly my wife and daughters who beared with me, when I neglected my family duties to prepare this manuscript. It was also a pleasure to work with the publishing team of Taylor & Francis and I express my sincere thanks to all members of this publishing team.

I am sure that this book is not free from mistakes in spite of my best efforts. The readers are most welcome to send their constructive suggestions to me either on the content of the book or on TWIN. Please write to me at [email protected].

Additional material is available from the CRC Press website: http://www.crcpress.com/product/isbn/9781482233360.

Sivaji Chakravorti

Jadavpur University

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