The following is a paper by H. Aspden published in Lettere al Nuovo Cimento, v. 38, pp. 243-246 (1983).
Abstract: Having regard to the developing interest in a lattice-structured vacuum in intepreting the structure of particles, an aspect of the electrically structured lattice model of the vacuum is discussed in relation to electric field energy. It is shown that a necessary condition is that the lattice should have planar boundaries. This implies a domain structure somewhat analogous to that found in ferromagnetic materials.
The subject of the paper is discussed elsewhere in these Web pages. See WHY HAWKING IS WRONG!. Several quoted sections are there included.