  The existence of attractions between like-charged colloids immersed in ionic
solution have been discovered in recent experiments. This phenomenon
contradicts the predictions of DLVO theory and indicates a failure of mean
field theory. We study a toy model based on a two dimensional one-component
plasma, which is exactly soluble at one particular coupling constant. We show
that colloidal interaction results from a competition between ion-ion repulsion
and longer ranged ion-void attraction.
