TOD

Abstract

It is well known that two co-axial vortex rings can leap-frog about each other. By direct numerical simulation, we show that in superfluid helium the effect can be generalised to a large number of vortex rings, which form a toroidal bundle. The bundle can be shown to be robust, travelling a significant distance compared to its diameter, whilst simultaneously becoming linked and eventually turbulent. We also discuss the effect of friction at non-zero temperatures, and show how in this case the presence of normal fluid rotation is necessary for the stability of the bundle.