  As an approach to describe the long-range properties of non-Abelian gauge
theories at non-zero temperature T < T_c, we consider a non-interacting
ensemble of dyons (magnetic monopoles) with non-trivial holonomy. We show
analytically, that the quark-antiquark free energy from the Polyakov loop
correlator grows linearly with the distance, and how the string tension scales
with the dyon density. In numerical treatments, the long-range tails of the
dyon fields cause severe finite-volume effects. Therefore, we demonstrate the
application of Ewald's summation method to this system. Finite-volume effects
are shown to be under control, which is a crucial requirement for numerical
studies of interacting dyon ensembles.
