Electrodynamics of Magnetoactive Media

Abstract

`Electrodynamics of Magnetoactive Media' is an unusual book in that it cuts across conventional physics discipline boundaries. The unifying theme allowing this is, quite simply, the physics of magnetic fields in various media. I believe the authors are correct in stating that the book is unique in specifically covering electrodynamic phenomena associated with magnetic fields, though of course some of the more elementary aspects are covered in the classical textbooks on electromagnetism, which are duly acknowledged. This interdisciplinarity makes the book very interesting to people with a range of backgrounds. For example, as a plasma physicist, I was familiar with most of the material on plasmas, but liquid crystals and superconductors were entirely new territory for me. These chapters were indeed both accessible and interesting, and it was surprising for me to see how much commonality there is in the physics of these various media. The first part of the book covers some fundamentals of electrodynamics and magnetostatics, and of electromagnetic waves. Most of this material is covered in textbooks on electromagnetism, and some of it is very basic (for example, LRC circuit theory, surely covered in most first year physics courses, is included) but it is perhaps a useful prelude for what is to come. The generic topic of charged particle motion in electromagnetic fields is well covered. Three main magnetoactive media are then discussed: plasmas (focusing on waves), liquid crystals and superconductors. It is all too easy to criticise a book on the grounds of omitted material, but I do feel that a chapter on magnetostatics in plasmas would have been very helpful, covering force-free fields and so on. Some interesting analogies could then have been exploited. For example, I was intrigued to discover an equation for magnetic fields in superconductors (equation (9.36)) which, apart from a change of sign, is identical to the Helmholtz equation used to\newpage\noindent model linear force-free fields in plasmas. Even more intriguingly, the mathematical solution then developed for a junction between a normal conductor and a superconductor is then almost identical to a solution I once published for the equilibrium of expanding plasma loops in the solar corona! The book is clearly written, and the level of mathematics is very appropriate for an advanced undergraduate or postgraduate text: the authors do not fall into the trap of superficially simplifying the description by omitting steps of mathematical arguments. It is a pity, however, that there are no examples or problems, ideally with solutions, which would have been very helpful if the book were to be used for teaching purposes. Nevertheless, because of the interdisciplinarity and the emphasis on fundamental physical principles unifying diverse applications, this book would be a very good basis for a course. Perhaps academics will be encouraged to introduce new lecture courses on this interesting topic. Every library should have a copy of this book, and it would be of interest to many individual researchers who would like to broaden their knowledge outside their own research fields.