  When masless excitations are limited or modified by the presence of material
bodies one observes a force atcing between them generally called Casimir force.
Such excitations are present in any fluid system close to its true bulk
critical point. We derive exact analytical results for both the temperature and
external ordering field behavior of the thermodynamic Casimir force within the
mean-field Ginzburg-Landau Ising type model of a simple fluid or binary liquid
mixture. We investigate the case when under a film geometry the boundaries of
the system exhibit strong adsorption onto one of the phases (components) of the
system. We present analytical and numerical results for the (temperature-field)
surface of the force in both the critical region of the film close to its
finite-size or bulk critical points as well as in the capillary condensation
regime below the finite-size critical point.
