  A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic
vortices represented by (closed) random surfaces, is presented. The random
surfaces, governed by an action penalizing curvature, are investigated using
Monte Carlo methods on a hypercubic lattice. A low-temperature confining phase
and a high-temperature deconfined phase are generated by this simple dynamics.
After fixing the parameters of the model such as to reproduce the relation
between deconfinement temperature and zero-temperature string tension found in
lattice Yang-Mills theory, a surprisingly accurate prediction of the spatial
string tension in the deconfined phase results. Furthermore, the Pontryagin
index associated with the lattice random surfaces of the model is constructed.
This allows to also predict the topological susceptibility; the result is
compatible with measurements in lattice Yang-Mills theory. Thus, for the first
time an effective model description of the infrared sector emerges which
simultaneously and consistently reproduces both confinement and the topological
aspects of Yang-Mills theory within a unified framework. Further details can be
found in hep-lat/9912003 and hep-lat/0004013, both to appear in Nucl. Phys. B.
