skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Vortex Multiplication in Applied Flow: A Precursor to Superfluid Turbulence

Abstract

A surface-mediated process is identified in {sup 3}He-B which generates vortices at a roughly constant rate. It precedes a faster form of turbulence where intervortex interactions dominate. This precursor becomes observable when vortex loops are introduced in low-velocity rotating flow at sufficiently low mutual friction dissipation at temperatures below 0.5T{sub c}. Our measurements indicate that the formation of new loops is associated with a single vortex interacting in the applied flow with the sample boundary. Numerical calculations show that the single-vortex instability arises when a helical Kelvin wave expands from a reconnection kink at the wall and then intersects again with the wall.

Authors:
; ;  [1];  [1];  [2];  [3]; ;  [4];  [5]
  1. Low Temperature Laboratory, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT (Finland)
  2. (Russian Federation)
  3. Physikalisches Institut, Universitaet Bayreuth, D-95440 Bayreuth (Germany)
  4. Department of Physics, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka 558-8585 (Japan)
  5. Department of Physical Sciences, P.O. Box 3000, FIN-90014 University of Oulu, Oulu (Finland)
Publication Date:
OSTI Identifier:
20778727
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevLett.96.085301; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; FRICTION; HELIUM 3; LIQUIDS; PRECURSOR; SUPERFLUIDITY; TURBULENCE; VORTICES; WALLS

Citation Formats

Finne, A.P., Kopu, J., Krusius, M., Eltsov, V.B., Kapitza Institute for Physical Problems, Kosygina 2, 119334 Moscow, Eska, G., Haenninen, R., Tsubota, M., and Thuneberg, E.V.. Vortex Multiplication in Applied Flow: A Precursor to Superfluid Turbulence. United States: N. p., 2006. Web. doi:10.1103/PHYSREVLETT.96.0.
Finne, A.P., Kopu, J., Krusius, M., Eltsov, V.B., Kapitza Institute for Physical Problems, Kosygina 2, 119334 Moscow, Eska, G., Haenninen, R., Tsubota, M., & Thuneberg, E.V.. Vortex Multiplication in Applied Flow: A Precursor to Superfluid Turbulence. United States. doi:10.1103/PHYSREVLETT.96.0.
Finne, A.P., Kopu, J., Krusius, M., Eltsov, V.B., Kapitza Institute for Physical Problems, Kosygina 2, 119334 Moscow, Eska, G., Haenninen, R., Tsubota, M., and Thuneberg, E.V.. Fri . "Vortex Multiplication in Applied Flow: A Precursor to Superfluid Turbulence". United States. doi:10.1103/PHYSREVLETT.96.0.
@article{osti_20778727,
title = {Vortex Multiplication in Applied Flow: A Precursor to Superfluid Turbulence},
author = {Finne, A.P. and Kopu, J. and Krusius, M. and Eltsov, V.B. and Kapitza Institute for Physical Problems, Kosygina 2, 119334 Moscow and Eska, G. and Haenninen, R. and Tsubota, M. and Thuneberg, E.V.},
abstractNote = {A surface-mediated process is identified in {sup 3}He-B which generates vortices at a roughly constant rate. It precedes a faster form of turbulence where intervortex interactions dominate. This precursor becomes observable when vortex loops are introduced in low-velocity rotating flow at sufficiently low mutual friction dissipation at temperatures below 0.5T{sub c}. Our measurements indicate that the formation of new loops is associated with a single vortex interacting in the applied flow with the sample boundary. Numerical calculations show that the single-vortex instability arises when a helical Kelvin wave expands from a reconnection kink at the wall and then intersects again with the wall.},
doi = {10.1103/PHYSREVLETT.96.0},
journal = {Physical Review Letters},
number = 8,
volume = 96,
place = {United States},
year = {Fri Mar 03 00:00:00 EST 2006},
month = {Fri Mar 03 00:00:00 EST 2006}
}
  • Vortex dynamics in 3He-B is divided by the temperature dependent damping into a high-temperature regime, where the number of vortices is conserved, and a low-temperature regime, where rapid vortex multiplication takes place in a turbulent burst. We investigate experimentally the hydrodynamic transition between these two regimes by injecting seed vortex loops into vortex-free rotating flow. The onset temperature of turbulence is dominated by the roughly exponential temperature dependence of vortex friction, but its exact value is found to depend on the injection method.
  • We report a transition in the vorticity generated by a grid moving in the B phase of superfluid {sup 3}He at T<<T{sub c}. The evolution of the vorticity after arresting the grid shows a dramatic change in the decay rate at a critical grid velocity. We believe this to reflect a sharp transition from ballistic vortex-ring production at low grid velocities to quantum turbulence at higher velocities and that independent isolated vortex rings provide the precursors to the developed turbulence. Furthermore we believe that this may be a feature of all quantum turbulence arising from repetitive mechanical agitation.
  • The behavior of a tangle of quantized vortex lines subject to uniform superfluid and normal-fluid driving velocities is investigated. The dynamical equation of the quantized vortices in the local approximation is supplemented by the assumption that when two such singularities cross, they undergo a reconnection. The properties of the dynamical equation, when combined with the assumption of homogeneity, imply numerous scaling relations, which are in fact observed experimentally. The primitive dynamical rules are utilized to perform extensive numerical simulations of the vortex tangle, using not only periodic, but also smooth-wall and rough-wall boundary conditions. All lead to the same homogeneousmore » vortex-tangle state, although the case of periodic boundary conditions requires an additional trick to eliminate artificial features. The quantitative results obtained from these simulations are found to be in excellent absolute agreement with a large variety of experiments, including recent studies of the vortex-tangle anisotropy.« less
  • Vortex turbulence generated by high-amplitude second sound in superfluid /sup 4/He is observed. Features of the transition to turbulence are similar to those seen in dc superfluid flow experiments. The measured frequency dependence of the critical velocity agrees with the predictions of dynamic scaling theory. The measured temperature dependence is similar to that of dc counterflow.
  • We present a comprehensive experimental study of the intrinsic fluctuations associated with superfluid turbulence. Fluctuations in the chemical potential and temperature difference for He II thermal counterflow in a small-diameter tube become extremely large at the T-I--T-II transition. This result is in qualitative agreement with a simple dynamical model of a transcritical bifurcation. The fluctuations in the fully developed T-II state are smaller than 0.1%, in accord with computer simulations of fluctuations in homogeneous superfluid turbulence. Consistent measurements of the power spectra, power amplitude, relaxation time, and steady-state vortex-line density are presented. Our results are in substantial disagreement with previousmore » measurements of fluctuations in superfluid turbulence. We suggest that the major discrepancy is due to unexpectedly large-amplitude fluctuations generated by macroscopic inhomogeneities in the vortex-line density present in the earlier experiments. Evidence from a variety of experiments, including our own measurements of externally driven fluctuations, supports this interpretation.« less