Electrodynamic phenomena induced by a dark fluid: Analogs of   pyromagnetic, piezoelectric, and striction effects
  We establish a new model of coupling between a cosmic dark fluid and electrodynamic systems, based on an analogy with effects of electric and magnetic striction, piezo-electricity and piezo-magnetism, pyro-electricity and pyro-magnetism, which appear in classical electrodynamics of continuous media. Extended master equations for electromagnetic and gravitational fields are derived using Lagrange formalism. A cosmological application of the model is considered, and it is shown that a striction-type interaction between the dark energy (the main constituent of the dark fluid) and electrodynamic system provides the universe history to include the so-called unlighted epochs, during which electromagnetic waves can not propagate and thus can not scan the universe interior. 
Alexander B. Balakin and Nadejda N. Dolbilova
gr-qc astro-ph.CO hep-th