volume | PIER Journals

Abstract

Admittance and impedance (Leontovich) matching conditions at the boundary of a good conductor find widespread usage in the formulation and (numerical) solution of electromagnetic problems. Starting with the known relationships at a stationary interface, we derive manifestly covariant admittance and impedance relations in a flat space-time for a conducting body which moves with uniform velocity in free space. Explicit formulas (in the ordinary space, that is) are given for both isotropic and anisotropic conductors. Under the same hypotheses, we also derive, at the conducting interface, the surface density of four-force by means of the normal component of the relevant energy-momentum tensor. The low-velocity limit of the formulas is also presented because it is of particular interest for practical applications. Moreover, since the covariant admittance and impedance relations as well as the matching condition of the energy-momentum tensor require the unitary four-vector perpendicular to a surface in motion, we outline, in the appendices, the derivation of unitary four-vectors tangential to a hyper-line and perpendicular to a hyper-surface in the Lorentz space.

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Dr. Vito Lancellotti