Scattering of Line-Ring Vortices in a Superfluid

TL;DR

This paper investigates how vortex rings scatter off a superfluid line vortex using Gross-Pitaevskii simulations, showing that a vortex filament model accurately predicts the scattering behavior across various impact parameters.

Contribution

It demonstrates the effectiveness of the vortex filament approximation in modeling vortex ring scattering in superfluids within a specific parameter regime.

Findings

Vortex filament model accurately predicts scattering dynamics.

Strong asymmetry observed in scattering based on initial offset.

Simulation results align with hydrodynamic approximations.

Abstract

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. By using a vortex extraction algorithm, we are able to track the location of the vortex ring as a function of time. Using this, we 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. 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.