An effective medium model for the electric conductivity of an N-component anisotropic and percolating mixture

An effective medium model for the DC conductivity of heterogeneous systems is presented that is fully symmetrical in the treatment of its components and can incorporate anisotropy. As a consequence, the new theory allows for percolation of a multitude of phases at realistic percolation thresholds. Computer simulations on simple isotropic and anisotropic systems have been carried out to support the model. The theory will be of importance for the modelling of conductivity phenomena in, e.g. rock formations.