Ov Lounasmaa Laboratory

Finland

Ov Lounasmaa Laboratory

Finland

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Hosio J.J.,Ov Lounasmaa Laboratory | Eltsov V.B.,Ov Lounasmaa Laboratory | Krusius M.,Ov Lounasmaa Laboratory | Makinen J.T.,Ov Lounasmaa Laboratory
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The dynamics of quantized vortices is studied in superfluid 3He-B after a rapid stop of rotation. We use Andreev reflection of thermal excitations to monitor vortex motion with quartz tuning-fork oscillators in two different experimental setups at temperatures below 0.2T c. Deviations from ideal cylindrical symmetry in the flow environment cause the early decay to become turbulent. This is identified from a rapid initial overshoot in the vortex density above the value before the spin-down and its subsequent decay with a t -3 /2 time dependence. The high polarization of the vortices along the rotation axis significantly suppresses the effective turbulent kinematic viscosity ν′ below the values reported for more homogeneous turbulence and leads to a laminar late-time response. The laminar dissipation down to T<0.15T c is determined from the precession frequency of the polarized vortex configuration. In the limit of vanishing normal-component density, it is found to approach a temperature-independent value, whose origin is currently under discussion. © 2012 American Physical Society.

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