The hydrodynamics of plasma ablation and the thermalization process of the target interior core with the surrounding corona, formed by the uniform irradiation of intense ion beams over the spherical target are investigated in detail. Starting from the basic equations for the ion beam, the ion beam penetration depth is calculated and the self-regulation condition for the hot corona is applied to describe the process of core-corona coupling. The effects of ion beam energy, ion beam mass, and the target electron density on the ion beam penetration depth are studied. As the relevant calculations reveal, it is interesting to note the existence of an optimum value of ion beam energy for which the core-corona coupling attains maximum value, beyond which further increase of the ion beam energy leads to the formation of more tenuous corona only and the target interior core begins to decouple from the surrounding corona.