  Within the model of topological particles (MTP) we determine the interaction
energy of monopole pairs, sources and sinks of a Coulombic field. The monopoles
are represented by topological solitons of finite size and mass, described by a
field without any divergences. We fix the soliton centres in numerical
calculations at varying distance. Due to the finite size of the solitons we get
deviations from the Coulomb potential at distances of a few soliton radii. We
compare the numerical results for these deviations with the running of the
coupling in perturbative QED.
