Hydrodynamic Decay of Decorated Quantum Vortex Rings

The decay of quantum vortex rings in HeII, visualized with the help of solid hydrogen particles trapped in their cores (which are regions of the flow with local pressure drop) [1,2], has been a problematic issue within the standard approach based on the two-fluid model of superfluidity [3]: the large drag exerted on the vortex rings by the flow of normal fluid past the hydrogen particles would ultimately lead to decay times that mismatch the ones measured in the laboratory, besides non-observed dynamical phenomena (as vortex ring rotation and contour deformation). Taking into account the so-called ``triple structure" of quantum vortex rings, as predicted by Kivotides et al. [4], we discuss a phenomenological solution of vortex ring decay puzzle, which is based on the fact that the vortex ring energy loss is accounted for not only by mutual friction, but also by the viscous dissipation and sweeping of the flow structures produced from the vortex ring backreaction on the normal component of the surrounding superfluid.
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References
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[1] G.P. Bewley, D.P. Lathrop, and K.R. Sreenivasan, Nature {\bf{441}}, 588 (2006).

[2] G.P. Bewley and K.R. Sreenivasan, J. Low Temp. Phys. {\bf{156}}, 84 (2009).

[3] K.W. Schwarz, Phys. Rev. B {\bf{31}}, 5782 (1985).

[4] D. Kivotides, C.F. Barenghi, and D.C. Samuels, Science {\bf{290}}, 777 (2000).