The dipole moment of a wall-charged void in a bulk dielectric

The dipole moment of a wall-charged void is examined with reference to the spatial extent of the surface charge density /spl sigma/ and the distribution of this charge. The salient factors influencing the void dipole moment are also examined. From a study of spherical voids, it is shown that, although the /spl sigma/-distribution influences the dipole moment, the spatial extent of /spl sigma/ has a greater influence. This behavior is not unexpected. For a void of fixed dimensions, the smaller the charged surface area, the greater is the charges, and thus the greater the dipole moment.<>