QFS 2016 Book of Abstracts

Abstracts

P3.6 Diffusion of Quantum Vortices Rickinson, Em, Baggaley, Andrew, Barenghi, Carlo

Newcastle University, School of Agriculture & Engineering (SAgE), School of Mathematics & Statistics, Herschel Building Newcastle University Newcastle upon Tyne NE1 7RU UK Symmetry breaking and the formation of topological defects through the Kibble-Zurek mechanism at the transition of 3 He to its superfluid phase is perhaps the best experimental analogy to the series of symmetry-breaking phase transitions in the early universe. In the Grenoble-Lancaster experiment [Nature 382.6589 (1996): 332-334] a region of superfluid 3 He is thermalised by a neutron capture event, then quenched through the superfluid phase transition by the surrounding fluid. This forms a localised area of quantised vorticity which spreads into the surrounding fluid. We simulate the spread of a region of quantised vortices with the point vortex model and the Gross-Pitaevskii equation in 2D. P3.7 Investigation of Saturation Effects on Turbulence Decay by a Confined Geometry Yang Jihee, Ihas Gary G. University of Florida, Department of Physics, P.O. Box 118440, Gainesville, FL, USA 32611-8440 The study of growth and decay of gird turbulence is standard in classical fluids, and has been pursued in quantum turbulence on small channels. We generate turbulence by pulling a grid through a much larger channel in superfluid 4 He. Turbulent intensity, ω , is measured using second sound. Supposedly ω decays by either ≈ t − 11 / 10 or ≈ t − 17 / 14 when energy containing eddies are growing. If eddies saturate at the channel size, it decays as ω ≈ t − 3 / 2 . Rates of decay and saturation are examined by a phase amplitude locked system. M. R. Smith, R. J. Donnelly, N. Goldenfeld, and W. F. Vinen, Phys. Rev. Lett. 71, 2583 (1993).; S. R. Stalp, L. Skrbek, and R. J. Donnelly, Phys. Rev. Lett. 82, 4831 (1999)

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