  We examine the formation of vortical "smoke rings" as a result of
thermalization of energy lost by a jet. We simulate the formation and evolution
of these rings using hydrodynamics and define an observable that allows to
probe this phenomenon experimentally. We argue that observation of vorticity
associated with jets would be an experimental confirmation of the
thermalization of the energy lost by quenched jets, and also a probe of shear
viscosity.
