Lookup NU author(s): Robert Cooper,
Dr Andrew Baggaley,
Professor Carlo Barenghi
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2019, The Author(s).Streamlines, vortex lines and magnetic flux tubes in turbulent fluids and plasmas display a great amount of coiling, twisting and linking, raising the question as to whether their topological complexity (continually created and destroyed by reconnections) can be quantified. In superfluid helium, the discrete (quantized) nature of vorticity can be exploited to associate to each vortex loop a knot invariant called the Alexander polynomial whose degree characterizes the topology of that vortex loop. By numerically simulating the dynamics of a tangle of quantum vortex lines, we find that this quantum turbulence always contains vortex knots of very large degree which keep forming, vanishing and reforming, creating a distribution of topologies which we quantify in terms of a knot spectrum and its scaling law. We also find results analogous to those in the wider literature, demonstrating that the knotting probability of the vortex tangle grows with the vortex length, as for macromolecules, and saturates above a characteristic length, as found for tumbled strings.
Author(s): Cooper RG, Mesgarnezhad M, Baggaley AW, Barenghi CF
Publication type: Article
Publication status: Published
Journal: Scientific Reports
Online publication date: 22/07/2019
Acceptance date: 05/07/2019
Date deposited: 09/09/2019
ISSN (print): 1571-0645
ISSN (electronic): 1873-1457
Publisher: Nature Publishing Group
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