Electromagnetics of superconductors

Summary form only given. It is pointed out that, electromagnetically speaking, a superconductor is distinguishable from a fictitious perfect conductor. A superconducting material is more conveniently treated as a dielectric material with a negative real part of the dielectric constant as far as electromagnetics is concerned. When superconductors are considered as a generalized dielectric material, some superconductive electromagnetic problems are simplified, since the dielectric parameter is an integral part of electromagnetic computation. No technical difficulty is presented to existing computer programs if a dielectric constant passes from a positive value to a negative one. Also presented is a time-domain computational method involving dispersive media, such as superconductors or plasma. It involves a time-domain finite difference approach with system function expansion, so that no explicit convolution is required. It thus greatly reduces memory demand and CPU time. As a consequence of this electromagnetic treatment of a superconductor, the existence of a surface wave on a superconducting surface is also predicted.<>