The Use of Computer Algebra in Maxwell's Theory

We present a small computer algebra program for use in Maxwell’s theory. The Maxwell equations and the energy-momentum current of the electromagnetic field are formulated in the language of exterior differential forms. The corresponding program can be applied (in the presence of a gravitational field) in curved Riemannian spacetime as well as in flat Minkowski spacetime in inertial or {\em non-inertial} frames. Our program is written for the computer algebra system REDUCE with the help of the EXCALC package for exterior differential forms.\par The two major advantages of this modern approch to electrodynamics — the natural formulation, free of both metric and coordinates, and the straightforward programming of problems — are illustrated by examining a number of examples ranging from the Coulomb field of a static point charge to the Kerr–Newman solution of the Einstein–Maxwell equations.