electric flux density

In physics, the electric displacement field (denoted by D), also called electric flux density, is a vector field that appears in Maxwell's equations. It accounts for the electromagnetic effects of polarization and that of an electric field, combining the two in an auxiliary field. It plays a major role in the physics of phenomena such as the capacitance of a material, the response of dielectrics to an electric field, how shapes can change due to electric fields in piezoelectricity or flexoelectricity as well as the creation of voltages and charge transfer due to elastic strains. The rate of change of D, ∂D/∂t, is the displacement current density.

Illustration of polarization due to a negative charge In any material, if there is an inversion center then the charge at, for instance,