Scattering of Line-Ring Vortices in a Superfluid

We study the scattering of vortex rings by a superfluid line vortex using the Gross–Pitaevskii equation in a parameter regime where a hydrodynamic description based on a vortex filament approximation is applicable. The scattering of a vortex ring by a line vortex is characterised by the initial offset of the centre of the ring from the axis of the vortex. We find that a strong asymmetry exists in the scattering of a ring as a function of this initial scattering parameter. Using a vortex extraction algorithm, we are able to track the location of the vortex ring as a function of time. We then show that the scattering of the vortex ring in our Gross–Pitaevskii simulations is well captured by the local induction approximation of a vortex filament model for a wide range of impact parameters. In contrast, the absorption of the ring by the line vortex is not predicted by the local induction approximation.