Finite speed of propagations of the electromagnetic field in nonlinear   isotropic dispersive mediums
  We propose some modification of Maxwell's equations describing mediums which electric and magnetic properties are changed essentially after interaction with outer electromagnetic field. We show for such mediums that electromagnetic waves have finite speed of propagations property for some time depending on initial energy of electromagnetic field and nonlinear parameters of the problem which are responsible for properties of medium. 
Yuliya V. Namlyeyeva, Roman M. Taranets