Charged multifluids in general relativity

The exact 1 + 3 covariant dynamical fluid equations for a multi-component plasma, together with Maxwellʹs equations are presented in such a way as to make them suitable for a gauge-invariant analysis of linear density and velocity perturbations of the Friedmann–Robertson–Walker model. In the case where the matter is described by a two-component plasma where thermal effects are neglected, a mode representing high-frequency plasma oscillations is found in addition to the standard growing and decaying gravitational instability picture. Further applications of these equations are also discussed.