The new entropy concept for the collective magnetic equilibria developed in preceding papers is applied to the description of the states of a Tokamak subjected to Ohmic and auxiliary heating. The condition of existence of steady-state plasmas with vanishing entropy production implies, on the one hand, the resilience of specific current density profiles and, on the other, severe restrictions on the scaling of the confinement time with power and current in the presence of Ohmic relaxation. These restrictions are consistent with the Goldston scaling and with the existence of a heat pinch.