In the so-called dielectric materials,the constituent atoms are considered to be ionize to a certain degree and are either positively or negatively charged
In such ionic crystals,when an electric field,
cations are attracted to the cathode and anions to the anode due to electrostatic interaction
The electron clouds also deform, causing electric dipoles
This phenomenon is known as the electric polarization of the dielectric, and the polarization is expressed quantitatively as the sum of the electric dipoles per unit volume
there are three kinds ; electronic, ionic and dipole reorientation-related polarizations.