Stability and Dissipation of Laminar Vortex Flow in Superfluid<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>3</mml:mn></mml:mmultiscripts><mml:mtext mathvariant="bold">−</mml:mtext><mml:mi mathvariant="bold">B</mml:mi></mml:math>

Eltsov, V. B.; Graaf, R. de; Heikkinen, P. J.; Hosio, J. J.; Hänninen, Risto; Krusius, M.; L'vov, V. S.

doi:10.1103/physrevlett.105.125301

Cited by 30 publications

(51 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The original measurements left an uncertainty (6) whether the accepted value of the gap should be renormalized to fit the experimental data. New measurements of friction to lower temperatures (9,10) leave no doubt that the bulk Δ properly describes the low-temperature dependence α ∝ expð−Δ=k B TÞ, in accordance with the theory.…”

Section: Coarse-grained Superfluid Dynamics and Mutual Frictionsupporting

confidence: 60%

“…In some cases, laminar flow can be exceptionally stable, like in the spindown of a cylindrical container to rest. Here a large perturbation, like tilting the sample cylinder by 30°from the rotation axis, is needed to turn the flow turbulent even at Re α ∼ 10 3 (9). This stability is in contrast to classical fluids, where the spin-down to rest is one of the most unstable flows (37).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Quantum turbulence in superfluids with wall-clamped normal component

Eltsov

Hänninen

Krusius

2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

In Fermi superfluids, such as superfluid 3 He, the viscous normal component can be considered to be stationary with respect to the container. The normal component interacts with the superfluid component via mutual friction, which damps the motion of quantized vortex lines and eventually couples the superfluid component to the container. With decreasing temperature and mutual friction, the internal dynamics of the superfluid component becomes more important compared with the damping and coupling effects from the normal component. As a result profound changes in superfluid dynamics are observed: the temperature-dependent transition from laminar to turbulent vortex motion and the decoupling from the reference frame of the container at even lower temperatures.superfluid Reynolds number | vortex tension | vortex front | rotating flow | pipe flow I n this paper, we consider the motion of quantized vortices in superfluids, where the normal component is clamped to the walls of the container; that is, it is stationary in a reference frame moving with the wall. This situation can be experimentally realized in superfluid 3 He. In such systems, turbulent motion can occur only in the superfluid component and thus, in principle, is easier to analyze. Here the role of the normal fluid is twofold: first, it provides friction in the superfluid motion, which is mediated by quantized vortices and works over a wide range of length scales. Second, it provides a coupling to the container walls, which acts uniformly over the whole volume of the superfluid. This situation is quite unlike classical turbulence, where viscous dissipation operates only at the small Kolmogorov scale and coupling to the walls is provided by thin boundary layers.As a result, a variety of new phenomena is observed in experiments and numerical simulations as a function of temperature. These phenomena are controlled by the normal-fluid density. At the highest temperatures, turbulent motion is suppressed completely. When the temperature decreases, a sharp transition to turbulence is seen. The transition can be characterized by a superfluid Reynolds number, which is composed of the internal friction parameters of the superfluid and is independent of velocity. When turbulence is triggered by a localized perturbation of the laminar flow, the critical value of the Reynolds number is found to scale with the strength of the perturbation.When the temperature decreases further, friction from the normal component rapidly vanishes. The overall dissipation rate in quantum turbulence remains nevertheless finite, owing to the contribution from the turbulent energy cascade, and reaches a temperatureindependent value in the zero-temperature limit. This zero-temperature dissipation can be characterized by an effective viscosity or friction. It is found, however, that coupling to the walls is not essentially improved by the turbulence and can potentially become very small. At the lowest temperatures the concept of a single effective friction breaks down; for the proper descriptio...

show abstract

Section: Coarse-grained Superfluid Dynamics and Mutual Frictionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Quantum turbulence in superfluids with wall-clamped normal component

Eltsov

Hänninen

Krusius

2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…14), mechanical resonator techniques were developed for quantum turbulence (15)(16)(17)(18), and quantum turbulence was studied in dilute gases (19,20); there were many important theoretical developments, for example refs. [21][22][23][24][25][26], and numerical methods were enormously improved (27)(28)(29) to complement and better interpret experimental results.…”

mentioning

confidence: 99%

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

Fisher

Jackson

Sergeev

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Andreev reflection of quasiparticle excitations provides a sensitive and passive probe of flow in superfluid 3 He-B. It is particularly useful for studying complex flows generated by vortex rings and vortex tangles (quantum turbulence). We describe the reflection process and discuss the results of numerical simulations of Andreev reflection from vortex rings and from quantum turbulence. We present measurements of vortices generated by a vibrating grid resonator at very low temperatures. The Andreev reflection is measured using an array of vibrating wire sensors. At low grid velocities, ballistic vortex rings are produced. At higher grid velocities, the rings collide and reconnect to produce quantum turbulence. We discuss spatial correlations of the fluctuating vortex signals measured by the different sensor wires. These reveal detailed information about the formation of quantum turbulence and about the underlying vortex dynamics. Quantum turbulence in superfluid 4 He has been studied for many decades (3-5). There has been a great deal of renewed interest in quantum turbulence in recent years owing to several factors: quantum turbulence was discovered in superfluid 3 He (6-8), techniques were developed to extend the study of quantum turbulence in superfluid 4 He to very low temperatures (9, 10), imaging techniques were developed to visualize superfluid turbulence at higher temperatures (11-13) (see the review in ref. 14), mechanical resonator techniques were developed for quantum turbulence (15-18), and quantum turbulence was studied in dilute gases (19,20); there were many important theoretical developments, for example refs. 21-26, and numerical methods were enormously improved (27-29) to complement and better interpret experimental results.In this article, we discuss quantum turbulence generated by vibrating grids in superfluid 3 He-B at low temperatures, where the normal fluid component is very small. The primary thermal excitations in 3 He are quasiparticle and quasihole excitations (30). At low temperatures, the excitation mean free path between collisions vastly exceeds the experimental dimensions. In this ballistic regime, excitations move independently and normally scatter only with the container walls. The normal fluid concept no longer applies because there is no collective motion of excitations.In addition to normal scattering, excitations can also undergo Andreev reflection. Andreev scattering produces nearly perfect retroreflection of excitations with very little momentum transfer: Quasiparticles become quasiholes, and vice versa. This provides an ideal probe for vortices and quantum turbulence at low temperatures. Andreev Scattering from Superfluid FlowThe dispersion curve for excitations is shown in Fig. 1A. The excitation group velocity v g = dE=dp is parallel to the momentum for quasiparticles that have p > p F , where p F is the Fermi momentum and is antiparallel to the momentum for quasiholes that have p < p F . The dispersion curve is tied to the reference frame of the superfluid. So, accordi...

show abstract

“…This hypothesis has been tested in both NMR [31] and Andreev reflection measurements [11] with similar conclusions. A straightforward well-defined measurement is obtained by recording the response to a sudden impulsive stop of rotation.…”

Section: Andreev Reflection From Moving Vorticesmentioning

confidence: 61%

ANDREEV REFLECTION IN ROTATING SUPERFLUID³He-B

B.¹,

J.²,

Krusius³

et al. 2014

ЖЭТФ

Self Cite

View full text Add to dashboard Cite

Andreev reflection of quasiparticle excitations from quantized line vortices is reviewed in the isotropic B phase of superfluid 3 He in the temperature regime of ballistic quasiparticle transport at T ≤ 0.20 Tc. The reflection from an array of rectilinear vortices in solid-body rotation is measured with a quasiparticle beam illuminating the array mainly in the orientation along the rotation axis. The result is in agreement with the calculated Andreev reflection. The Andreev signal is also used to analyze the spin down of the superfluid component after a sudden impulsive stop of rotation from an equilibrium vortex state. In a measuring setup where the rotating cylinder has a rough bottom surface, annihilation of the vortices proceeds via a leading rapid turbulent burst followed by a trailing slow laminar decay from which the mutual friction dissipation can be determined. In contrast to currently accepted theory, it is found to have a finite value in the zero temperature limit: α(T → 0) = (5 ± 0.5) · 10 −4 .

show abstract

Stability and Dissipation of Laminar Vortex Flow in SuperfluidHe3−B

Cited by 30 publications

References 13 publications

Quantum turbulence in superfluids with wall-clamped normal component

Quantum turbulence in superfluids with wall-clamped normal component

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

ANDREEV REFLECTION IN ROTATING SUPERFLUID³He-B

Contact Info

Product

Resources

About

Stability and Dissipation of Laminar Vortex Flow in SuperfluidHe3−B

Cited by 30 publications

References 13 publications

Quantum turbulence in superfluids with wall-clamped normal component

Quantum turbulence in superfluids with wall-clamped normal component

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in 3 He-B

ANDREEV REFLECTION IN ROTATING SUPERFLUID3He-B

Contact Info

Product

Resources

About

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

ANDREEV REFLECTION IN ROTATING SUPERFLUID³He-B