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Book Review: Electromagnetics: Classical and Modern Theory and Applications

Electromagnetics: Classical and Modern Theory and Applications: SAMUEL SEELY and ALEXANDER D. POULARIKAS (Marcel Dekker, 1979,790 pp., £15.00) Introduction to Electrodynamics: DAVID J. GRIFFITHS (Prentice-Hall, 1981,479 pp., £15.55) There are dozens of books on electromagnetism. They can be broadly divided into two categories: those written for engineers, and those aimed principally at physicists. Most of the books in the former category concentrate on high-frequency applications with communications engineers chiefly in mind, and there are relatively few that cater for the broadly-based electrical engineer with adequate coverage of such low-frequency topics as eddy-currents and the calculation of static field distributions. One of the best of these was Seely's Introduction to Electromagnetic Fields, now long out of print, and there must be many academics confronted with the task of teaching electromagnetism to a mixed class of electrical engineers who regret that it is no longer available. The book by Seely and Poularikas is in no sense a revision of Seely's earlier book, but a much more extensive and altogether more ambitious text. It is not obvious what sort of readership it is aimed at. It is apparently written for engineers, but much of the subject matter is treated in a highly analytical manner that will prove hard going for most practising engineers, and although the book discusses applications, these are mostly rather specialised topics such as fibre optics and the properties of plasmas. It is essentially a book for scholars. An unusual feature is that it seeks to present a unified treatment of vector fields and wave phenomena which brings out the similarities between many branches of physics and engineering. Thus potential-flow fields are introduced with reference to fluid-flow and heat conduction, as well as to electric and magnetic fields; and the treatment of wave phenomena includes acoustic waves, crystal optics, and Schrodinger waves. The treatment is comprehensive and scholarly, but the rather mathematical approach does not make for easy reading. It is certainly not a book for undergraduates, though teachers and researchers whose work involves advanced problems in electromagnetism will find much of interest in it. The book by Griffiths is written for physicists and contains several advanced topics of a rather rarified nature (e.g. the Maxwell stress-tensor and relativistic electrodynamics) that are of marginal interest to engineers. It avoids any discussion of applications. The treatment seems to be on two different levels. The basic ideas of vector operators are presented in a very qualitative way, with considerable reliance on physical intuition; there is, for example, no formal definition of curl (as the ratio of the line-integral around an infinitesimally small curve to the area enclosed), nor any detailed derivation of Stoke's theorem. By contrast, the treatment of more advanced topics such as Poynting's theorem tends to be rather mathematical, without much discussion of the underlying physics. I would personally prefer to pursue a middle course between these two extremes, since either of them alone can present difficulties to the student. The style is generally racy ('How Maxwell fixed up Ampere's Law') and very readable, and many of the comments are helpful and thought-provoking. However, I cannot see this book displacing any of the more established texts for physicists, such as the classic one by Lorrain and Corson. E. H. RHODERICK, Professor ofSolid State Electronics, UMIST.