An Alternative Expression of The Poynting Vector Operating in a Confined Region of Evanescent Waves: Natural Function in The Method of Single Expression

Abstract

An alternative expression of the Poynting vector is presented. This expression is an intrinsic function at the electromagnetic wave description in the method of single expression (MSE). The MSE does not represent solutions of the Helmholtz equation as a sum of counterpropagating waves that permits to operate with an alternative expression for the Poynting vector. At the boundary problems solution carried out numerically by the MSE spatial distributions of electric and magnetic field amplitudes and the Poynting vector are obtained. An alternative expression of the Poynting vector is applicable both in confined media of a positive product of permittivity and permeability and of a negative product, that is relevant to the region of evanescent waves. The expression of the Poynting vector in the MSE is in complete agreement with the traditional representation of the Poynting vector.