Foundations of Electrodynamics

Parry Moon, Domina Eberle Spencer, Domina Eberle Spencer

• Publisher: Dover Publications
• Year: 2013
• ISBN:
  9780486316109
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Defined by the authors as "a serious attempt to develop electrodynamics on a postulational basis and to define each concept in the most general way, " this advanced undergraduate text takes a logical rather than historical approach. The treatment presupposes some knowledge of electricity and magnetism, making substantial use of vector analysis.
The first ten chapters employ a nonrelativistic perspective, covering fields, basic concepts, Maxwell's equations, charges with no relative motion and charges in uniform motion, accelerated charges, skin effect, waves, wave guides, and antennas. The final two chapters explore moving systems and relativistic electrodynamics. Numerous figures illuminate the text, and appendixes offer useful information on notation, differential equations, and other topics.

Chapter 1

FIELDS

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Traditional training in electrical engineering emphasizes circuit theory. Even where the phenomena have little or no similarity to circuit phenomena, the attempt is usually made to force the problem into the Pro crustean bed of circuit theory, as in the treatment of the magnetic “circuit” and the thermal “circuit.” Field theory, a powerful tool in the handling of problems in physics and engineering, has often been regarded as too abstruse for the engineer. But modern developments in science and industry have changed these ideas and have emphasized the desirability of training in field theory for both physicist and engineer, even at the undergraduate level.

As long as electrical applications dealt with direct currents or with alternating currents at power frequencies, the circuit approach was satisfactory for most purposes. But as frequencies were raised and as the importance of radio and radar increased, lumped-circuit theory became increasingly inadequate and the need arose for a more basic treatment of electrodynamics.

Such a basic treatment is given by Maxwell’s equations. These four equations may be considered as a condensed expression of the electromagnetic experience of the human race. A century and a half of electrical experiment is subsumed in Maxwell’s equations, the customary methods of calculation given in elementary textbooks being merely special cases of these general equations.

To make use of Maxwell’s equations, however, one should be familiar with vector analysis, particularly with the ideas of gradient, divergence, and curl. Such subjects are treated briefly in this introductory chapter. Basic concepts leading to Maxwell’s equations are considered in Chaps. 2 and 3. The remainder of the book is primarily a study of how to apply Maxwell’s equations to a wide variety of subjects, ranging from electrostatics to waveguides and antennas.

1-01. Fields and Coordinate Systems. Consider a specific region

: for instance, the interior of a sphere, or any other definite portion of space in which a physical phenomenon is to be studied. Next select a specific quantity, such as pressure, temperature, or electric field strength. Imagine that this quantity is measured at each point in region

. With each point of

is then associated a numerical measurement. The totality of these measurements constitutes a physical field.†

Note that two arbitrary choices have been made:

(1)...

Table of contents

• Cover
• Title Page
• Copyright Page
• Contents
• Preface
• 1 Fields
• 2 Basic Concepts
• 3 Maxwell’s Equations
• 4 Charges With No Relative Motion
• 5 Charges In Uniform Motion
• 6 Accelerated Charges
• 7 Skin Effect
• 8 Waves
• 9 Waveguides
• 10 Antennas
• 11 Moving Systems
• 12 Relativistic Electrodynamics
• Appendix
• Index