  Recently an electric and magnetic field correlator appearing in the
description of the heavy quarkonium system was evaluated on the lattice. Here,
we give a nonperturbative analytical evaluation of this field correlator using
a dual description of long distance Yang--Mills theory and using the stochastic
vacuum model. The two predictions are both compatible with lattice data but
show a different dependence on the quark separation. We discuss the analytic
results in relation to the lattice data.
