Source region electric field derivation by a dyadic green´s function approach

The electric field within a source region is derived by use of a vector form of Green´s second identity. The expression obtained is identical to that previously derived1 by a less direct method, but the present approach exposes the need to assume continuity of current density and electric field. The analysis gives the extra dyadic which must be added to the customary superposition integral to take account of the source-point singularity of the electric dyadic Green´s function.