 Spherical Neumann dipole images

For a current dipole in a homogeneous insulating sphere of radius $a$, let $\lambda =r^2/a^2$ and let $\Psi$ be its primary electric potential. The displayed representation solves the interior Neumann boundary condition up to an additive constant. It rewrites the spherical Kelvin transform correction and a distributed dipole correction using the dipole line-integral identity. The image parameters depend on the observation radius; this is an exact parametrized representation rather than a fixed collection of image source positions.