  We obtain the self-interaction for a point charge in the space-time of a
cylindrical thin-shell wormhole connecting two identical locally flat
geometries with a constant deficit angle. Although this wormhole geometry is
locally indistinguishable from a cosmic string background, the corresponding
self-forces are different even at the qualitative level. In fact in the cosmic
string geometry the force is always repulsive while for the wormhole background
we find that the force may point outwards or towards the wormhole throat
depending on the parameters of the configuration. These results suggest that
the study of the electromagnetic fields of charged particles is a useful tool
for testing the global properties of a given background.
