STABILITY OF VORTEX RINGS IN A MODEL OF SUPERFLOW

Stability of an isolated vortex ring is studied in the framework of th e Ginzburg-Landau model using the nonlocal equation of motion. It is s hown that an instability which might have been caused by nonlocal effe cts in the long-scale theory falls into the range of wavelengths compa rable with the healing length. A higher-order effect of acoustic emiss ion is found to play a stabilizing role, since the dissipation of the energy of perturbations by isotropic emission is sufficiently strong t o restore the circular shape with only a small loss of the momentum.