up in the Coulomb gauge [@zw2; @as1; @as2; @as3].

In the Coulomb gauge the $A^0$ component of the 4-vector potential results in an instantaneous interaction (potential) between color charges. Unlike QED, where the corresponding potential is a function only of the relative distance between the electric charges, in QCD it is a functional of the transverse gluon components, ${\bf A}$ [@clee]. Thus the numerical value of the potential cannot be obtained without knowing the correct wave functional of the state and its dependence on the gluon coordinates. So in QCD the chromo-electric field is expected to be non-local and to depend on the global distribution of charges, which set up the gluon wave functional.

Even though the exact solution to the general many-body problem is unavailable it is often possible to obtain good approximations if the dominant correlations can be identified. In Coulomb gauge QCD (in the Schrödinger field representation) the domain of the transverse gluon field, $\A$ is bounded and non-flat, and is referred to as the Gribov region. It is expected that the strong interaction between static charges originates from the long-range modes near the boundary of the Gribov region, the so called Gribov horizon. For example it 