Superfluid Vortex Interactions
Professor Joel Koplik (City College of NY)
We study the interactions between superfluid vortex filaments and
rings, with emphasis on annihilation and reconnection events. The
calculation is based on efficient numerical solutions of the
Gross-Pitaevskii nonlinear Schroedinger equation model of superfluid
He~II, so as to include physically reasonable core-scale dynamics. The
motivation is firstly to consider the maintenance and generation of
vorticity in superfluid flows, and secondly to compare the behavior of
superfluids and normal (Navier-Stokes) fluids with regard to the
evolution of vortex structures. In general it is found that
neighboring vortex filament sections of opposite orientation always
annihilate smoothly at the core scale, and otherwise the behavior is
very similar to that of normal fluid vortices. Collisions of vortex
rings resemble the scattering of elementary particles.