  We discuss finite regions of the deconfining phase of a confining gauge
theory (plasma balls/kinks) as solitons of the large $N$, long wavelength,
effective Lagrangian of the thermal gauge theory expressed in terms of suitable
order parameters. We consider a class of confining gauge theories whose
effective Lagrangian turns out to be a generic 1 dim. unitary matrix model. The
dynamics of this matrix model can be studied by an exact mapping to a
non-relativistic many fermion problem on a circle. We present an approximate
solution to the equations of motion which corresponds to the motion (in
Euclidean time) of the Fermi surface interpolating between the phase where the
fermions are uniformly distributed on the circle (confinement phase) and the
phase where the fermion distribution has a gap on the circle (deconfinement
phase). We later self-consistently verify that the approximation is a good one.
We discuss some properties and implications of the solution including the
surface tension which turns out to be positive. As a by product of our
investigation we point out the problem of obtaining time dependent solutions in
the collective field theory formalism due to generic shock formation.
