BAG PICTURE OF THE EXCITED QCD VACUUM WITH STATIC Q(Q)OVER-BAR SOURCE

The gluon excitations of the QCD vacuum are investigated in the presen ce of a static quark-antiquark source. It is shown that the ground sta te potential and the excitation spectrum of dynamical gluon degrees of freedom, as determined in our lattice simulations, agree remarkably w ell with model predictions based on the diaelectric properties of the confining vacuum described as a dual superconductor. The strong chromo electric field of the static Q (Q) over bar source creates a bubble (b ag) in the condensed phase where weakly interacting gluon modes can be excited. Some features and predictions of the bag model are presented and the chromoelectric vortex limit at large quark-antiquark separati on (string formation) is briefly discussed.