Classical electrodynamics without the Lorentz condition: Extracting energyfrom the vacuum

It is shown that if the Lorentz condition is discarded, the Maxwell-Heavisi de field equations become the Lehnert equations, indicating the presence of charge density and current density in the vacuum. The Lehnert equations ar e a subset of the O(3) Yang-Mills held equations. Charge and current densit y in the vacuum are defined straightforwardly in terms of the vector potent ial and scalar potential, and are conceptually similar to Maxwell's displac ement current, which also occurs in the classical vacuum. A demonstration i s made of the existence of a time dependent classical vacuum polarization w hich appears if the Lorentz condition is discarded. Vacuum charge and curre nt appear phenomenologically in the Lehnert equations but fundamentally in the O(3) Yang-Mills theory of classical electrodynamics. The latter also al lows for the possibility of the existence of vacuum topological magnetic ch arge density and topological magnetic current density. Both O(3) and Lehner t equations are superior to the Maxwell-Heaviside equations in being able t o describe phenomena not amenable to the latter. In theory, devices can be made to extract the energy associated with vacuum charge and current.