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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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