  The existence of quantized vortices is a key feature of Bose-Einstein
condensates. In equilibrium condensates only quantum vortices of unit
topological charge are stable, due to the dynamical instabilities of multiply
charged defects, unless supported by strong external rotation. Due to immense
fundamental interest in the physics of these fundamental topological
excitations, a great deal of work has been expended towards understanding ways
to force their stability. Here we show that in photonic Bose-Einstein
condensates of exciton-polariton quasiparticles pumped in an annular geometry,
not only do the constant particle fluxes intrinsic to the system naturally
stabilize multiply charged vortex states, but that such states can indeed form
spontaneously during the condensate formation through a dynamical symmetry
breaking mechanism. We elucidate the properties of these novel states, notably
finding that they radiate acoustically, in a process analogous to the emission
of gravitational waves from binary black holes. Finally, we show that the
vorticity of these photonic fluids are fundamentally limited by a quantum
Kelvin-Helmholtz instability, and therefore by the condensate radius and
pumping intensity. This represents the first report of this instability -
deeply fundamental in fluid dynamics - in a quantum photonic fluid.
