Dynamic Remanent Vortices in Superfluid 3He-B

Solntsev, R. E.; Graaf, R. de; Eltsov, V. B.; Hänninen, Risto; Krusius, M.

doi:10.1007/s10909-007-9380-3

Cited by 15 publications

(29 citation statements)

References 8 publications

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“…This turns out to yield different values for Ton. With ∆t = 2 min, the number of remanent vortices N i is about ten times larger (approximately 60 at about 0.53 Tc) than with ∆t = 20 min (approximately 10 at about 0.47 Tc) [10]. Because of the lower seed vortex density in the latter case, the onset moves from 0.53 Tc to 0.47 Tc.…”

Section: Introductionmentioning

confidence: 86%

“…Since the vortex number is reliably conserved during vortex formation processes only above 0.6 Tc, a particular rotating state generally has to be formed at high temperatures, but can then be cooled to low temperatures at constant rotation. In particular, to have a rotating vortex-free sample at low temperatures, the procedure is to warm up first above 0.6 Tc, where the annihilation of remnants is rapid [10]. The sample is kept there at zero rotation for 10 to 20 min and is then cooled down in rotation (with Ω < vc,exp/R).…”

Section: Measurements On Single-vortex Instabilitymentioning

confidence: 99%

“…The measurement starts from an initial state which is obtained by decelerating an equilibrium vortex state at 1.7 rad/s to Ω = 0 at a rate 0.01 rad/s 2 . The remaining vortices are left to annihilate [10] for a period ∆t at Ω = 0. Rotation is then increased to Ω f at a rate 0.02 rad/s 2 .…”

Section: Introductionmentioning

confidence: 99%

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The Dynamics of Vortex Generation in Superfluid 3He-B

et al. 2008

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A profound change occurs in the stability of quantized vortices in externally applied flow of superfluid 3 He-B at temperatures 0.6 Tc, owing to the rapidly decreasing damping in vortex motion with decreasing temperature. At low damping an evolving vortex may become unstable and generate a new independent vortex loop. This single-vortex instability is the generic precursor of turbulence. We investigate the instability with non-invasive NMR measurements on a rotating cylindrical sample in the intermediate temperature regime (0.3 -0.6) Tc. From comparisons with numerical calculations we interpret that the instability occurs at the container wall, when the vortex end moves along the wall in applied flow.Keywords quantized vortex · vortex formation · vortex instability · vortex dynamics · turbulence · transition to turbulence · mutual friction · rotating flow · vortex remanence PACS 67.57.Fg · 47.32.-y · 67.40.Vs

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Section: Introductionmentioning

confidence: 86%

Section: Measurements On Single-vortex Instabilitymentioning

confidence: 99%

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The Dynamics of Vortex Generation in Superfluid 3He-B

et al. 2008

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“…In this paper we compare the measured NMR response with the calculated spectra quantitatively. We start by reminding about the hydrostatic model of superfluid 3 He-B in a cylindrical geometry [7,8]. We discuss the superfluid order parameter textures, textural energies in applied flow and the relation to NMR.…”

Section: Introductionmentioning

confidence: 99%

“…There is ambiguity in the terminology in different publications: a) flare out and flare in is sometimes used instead of parted and extended flare out; b) flare out sometimes refers to both parted and extended flare out texture[3,14,24] …”

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confidence: 99%

Textures of Superfluid 3He-B in Applied Flow and Comparison with Hydrostatic Theory

et al. 2011

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Measurements of the order parameter texture of rotating superfluid 3 He-B have been performed as a function of the applied azimuthal counterflow velocity down to temperatures of 0.2 T c . The results are compared to the hydrostatic theory of 3 He-B. Good agreement is found at all measured temperatures and rotation velocities when the flow anisotropy contribution to the textural free energy is adjusted. This gives a superfluid energy gap ∆(T ) which agrees with that measured by Todoshchenko et al., with ∆(0) = 1.97 k B T c at 29.0 bar. The B-phase susceptibility, longitudinal resonance frequency, and textural phase transition have been extracted from the measurements as a function of temperature and azimuthal counterflow velocity. Owing to decreasing absorption intensities the present measuring method, based on the line shape analysis of the NMR spectrum, loses its sensitivity with decreasing temperature. However, we find that in practice the measurement of vortex numbers and counterflow velocities is still feasible down to 0.2 T c

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Transition to Superfluid Turbulence

Eltsov

Krusius²,

Volovik

2006

J Low Temp Phys

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Turbulence in superfluids depends crucially on the dissipative damping in vortex motion. This is observed in the B phase of superfluid 3He where the dynamics of quantized vortices changes radically in character as a function of temperature. An abrupt transition to turbulence is the most peculiar consequence. As distinct from viscous hydrodynamics, this transition to turbulence is not governed by the velocity-dependent Reynolds number, but by a velocity-independent dimensionless parameter 1/q which depends only on the temperature-dependent mutual friction -- the dissipation which sets in when vortices move with respect to the normal excitations of the liquid. At large friction and small values of 1/q < 1 the dynamics is vortex number conserving, while at low friction and large 1/q > 1 vortices are easily destabilized and proliferate in number. A new measuring technique was employed to identify this hydrodynamic transition: the injection of a tight bundle of many small vortex loops in applied vortex-free flow at relatively high velocities. These vortices are ejected from a vortex sheet covering the AB interface when a two-phase sample of 3He-A and 3He-B is set in rotation and the interface becomes unstable at a critical rotation velocity, triggered by the superfluid Kelvin-Helmholtz instability.Comment: Short review; to be published in Journal of Low Temperature Physics (2006

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Dynamic Remanent Vortices in Superfluid 3He-B

Cited by 15 publications

References 8 publications

The Dynamics of Vortex Generation in Superfluid 3He-B

The Dynamics of Vortex Generation in Superfluid 3He-B

Textures of Superfluid 3He-B in Applied Flow and Comparison with Hydrostatic Theory

Transition to Superfluid Turbulence

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