  A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic
vortex degrees of freedom represented by (closed) random world-surfaces, is
presented. The model quantitatively describes both the confinement properties
(including the finite-temperature transition to a deconfined phase) and the
topological susceptibility of the Yang-Mills ensemble. A (quenched) study of
the spectrum of the Dirac operator furthermore yields a behavior for the chiral
condensate which is compatible with results obtained in lattice gauge theory.
