Electrostatic energy when dielectrics are present: A general integral approach

A detailed discussion of electric energy storage in the presence of dielectrics is presented. The discussion is general and is aimed at the introductory–intermediate levels, when an integral representation of the laws of electrostatics is more familiar to the student. The case where a discrete set of point charges is slowly transported into the vicinity of an arbitrary dielectric is first considered and then an extension to the continuous distribution is presented. A simple model of atomic polarization is introduced and used to illustrate dielectric nonlinearities and the concept of self‐interaction. It is shown that the energy density E⋅D/2 is restricted to the case of linear dielectrics and a novel way of introducing Maxwell’s displacement current term at a more advanced level is suggested as a natural extension of the electrostatic case.