  A model for the infrared sector of Yang-Mills theory based on magnetic
vortices represented by (closed) random surfaces is investigated using lattice
Monte Carlo methods. The random surfaces are governed by a surface area action
and a curvature action. The model generates a finite-temperature deconfinement
transition; the coupling constants of the model can be chosen such as to
reproduce the SU(2) Yang-Mills ratio of the deconfinement temperature to the
square root of the zero-temperature string tension, T_c / sqrt{sigma_0} =0.69.
This yields a physical trajectory in the space of coupling constants on which
the confinement properties are approximately invariant. An at first sight
surprisingly accurate prediction of the spatial string tension in the
deconfined phase results, which can be made plausible in view of the specific
space-time structure of the vortex configurations in this phase. The
confinement properties are shown to be intimately tied to the percolation
properties of the vortex surfaces.
