Probing the interior of the Colour Flux Tube

In the dual superconductivity description of quark confinement the core of the flux tube connecting a quark pair belongs to a deconfined, hot phase. This can be checked in numerical experiments on 3D $Z_2$ gauge model. It is also pointed out that the Svetitsky-Yaffe conjecture provides analytic expressions for the distribution of the flux density around quark sources at critical temperature.