  The persistent current in three-dimensional mesoscopic rings is investigated
numerically. The model is tight-binding one with random site-energies and
interaction between electrons. The self-consistent Hartree-Fock approximation
is adopted for the interaction between electrons, and models with up to
$6\times 6\times 20$ sites are investigated. It is shown that the long-range
Coulomb interaction enhances the persistent current for rings with finite
width. The origin of the enhancement is discussed.
