On the possibility of electromagnetic surface waves

Abstract

The question of electromagnetic surface waves propagating along a plane of discontinuity between two different media was the subject of some diversity of opinion. It is related to the equally unsettled question about the merits of the conflicting solutions given by A. Sommerfeld (1) and H. Weyl (2) for the field of an electric dipole oscillating at the surface of a plane earth. A few remarks about this relation will be made in section 5, but its complete discussion will be postponed until a later date, and the present paper will be devoted to the analysis of the independent surface wave. It will be well, therefore, to define what is meant by this term. It is a matter of common knowledge that an ordinary plane wave, falling under an angle on a surface of discontinuity and suffering total reflection in the process, produces in the second medium an inhomogeneous wave with propagation parallel to the surface of discontinuity. But this may be called a dependent surface wave because it is only an adjunct of the space waves in the first medium and would not exist without them. On the other hand, an independent surface wave is one which consists of two inhomogeneous waves-one in each medium-running along the dividing surface. Its intensity is appreciable only in a thin layer along the surface of discontinuity and decreases exponentially to both sides.