  The Proca theory of the real massive vector field admits non-equilibrium
solutions, where the asymptotic dynamics of the electric field is dominated by
the periodically oscillating Coulomb component. We discuss how such field
configurations are seen in different reference frames, where we find an
intriguing spatial pattern of the vector field and the electromagnetic field
associated with it. Our studies are carried out in the framework of the
classical Proca theory.
