Heat flow in superfluid 3He

Johnson, R. T.; Kleinberg, R.L.; Webb, Richard A.; Wheatley, J. C.

doi:10.1007/bf00116140

Cited by 85 publications

(21 citation statements)

References 17 publications

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“…In high magnetic field, strong coupling effect must be considered for maximum gap parameter, and on normal fluid density components of the A 1 and A 2 phases of liquid He wire and torsional-oscillator viscometers [12] and down to T/T c 0.3 by a vibrating-wire viscometer [13]. Experimentally, the shear viscosity of the A phase has been measured by Alvesalo et al [14][15][16] in a vibrating string viscometer experiment and indirectly by Johnson et al [17]. The shear viscosity, in the presence of low magnetic field, has been measured by Alvesalo et al [16].…”

Section: Introductionmentioning

confidence: 99%

Shear viscosity of superfluid 3He–A1 at low temperatures

Shahzamanian

Afzali

2004

Annals of Physics

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Section: Introductionmentioning

confidence: 99%

Shear viscosity of superfluid 3He–A1 at low temperatures

Shahzamanian

Afzali

2004

Annals of Physics

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“…1 " 3 In this paper we report new measurements on the superfluid phases of 3 He in undirectional and oscillatory flow of frequency 0-40 Hz through a narrow rectangular channel of cross section approximately 48 /im (between polished faces)x2.86 mm and length 9.16 mm at temperatures down to T/T c = 0.52. The special characteristics of our experiments are a high sensitivity to dissipation, a wide range of driven flow currents, and direct observation of flow.…”

mentioning

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Dissipation in the Flow ofHe3-Aand
Dahm
¹
,
Betts
²
,
Brewer
³

et al. 1980
Phys. Rev. Lett.
62
1
9
0
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Measurements are reported which relate to the dissipation and superfluid density of 3 Ue-A and 3 He-i3 flowing through a long rectangular channel of cross section 48 nm x 2.86 mm at currents between 5x io" 2 g cm" 2 sec" 1 and 5>< 10" 5 g cm" 2 sec" 1 and at temperatures down to T/T c = 0.52. The results show a complex velocity dependence in both phases.PACS numbers: 67.50.Fi Several reported flow observations on superfluid 3 He are consistent with a two-fluid model in which the viscosity of one component is small or zero up to a critical velocity where dissipation sets in. 1 " 3 In this paper we report new measurements on the superfluid phases of 3 He in undirectional and oscillatory flow of frequency 0-40 Hz through a narrow rectangular channel of cross section approximately 48 /im (between polished faces)x2.86 mm and length 9.16 mm at temperatures down to T/T c = 0.52. The special characteristics of our experiments are a high sensitivity to dissipation, a wide range of driven flow currents, and direct observation of flow. These characteristics have enabled us to observe many new phenomena: most notably, in 3

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“…Johnson etal. 6 observed the heatflow of 3 He in 2-and 3mm-diam tubes and have inferred critical velocities between 0.2 and 0.8 mm/sec in the A phase, whereas in the B phase they obtain values of 4 to 5 mm/sec. The temperature dependence is not discussed by these authors.…”

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Critical Velocities in SuperfluidHe3

Parpia

Reppy

1979

Phys. Rev. Lett.

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diet an ordering temperature of 28 ± 5 K. An equivalent calculation for a more compressed lattice with the same nearest-neighbor spacing as the dense-solid phase but with molecular axes allowed to tilt out of the film plane gave approximately the same ordering temperature, 9 the closer spacing being compensated by the formation of a rickrack configuration of the molecular axes. That a model which treats the surface film as an idealized, two-dimensional structure gives results in good agreement with the experimental observations is testimony to the essentially twodimensional character of the transition.Finally, we have to address the question of what are the ordered-state molecular configurations of the registered and dense-solid films. This would be a difficult problem even if we were dealing with a three-dimensional solid. If that were the case, we would expect to be able to deduce the ordered configuration from the intensity profile of the diffraction pattern, 10 assuming sufficient diffraction data could be collected. But there is too much background scattering from the substrate (particularly at larger scattering vectors) to make such an approach feasible with overlayer films. The only realistic alternative is to attempt to compare the observed intensities with those calculated assuming ordered configurations suggested by theory. We find, unfortunately, that either the two-or four-sublattice configuration can satisfactorily reproduce the observed diffraction profile of the registered-solid phase; the data available are not sufficient to allow us to choose between the two suggested alternatives. One other possibility remains, namely, to search for the extra super lattice reflections expected if the ordered state is the four-sublattice rather than two-sublattice configuration. As it happens, this too appears to be impractical; a calculation of the relevant structure factors makes it clear that none of the extra reflections could be detected with neutrons. Thus we are forced to conclude that, while we can study the onset and development of orientational order in the nitrogen overlayer, we cannot, at least at this time, determine the ordered configuration.We wish to express our appreciation to W. Press for a number of helpful suggestions and to M. L. Klein for making available to us the results of unpublished computations.The oscillatory flow of superfluid s He through an 18-/rni-diam orifice has been studied. A clearly defined critical velocity is seen in both the A and B phases. For velocities greater than the critical value, the superflow involves an excess dissipation. The temperature dependence of the critical velocity is reported for temperatures near the superfluid transition (T/T c >0.9).The possibility of dissipationless flow is one of the mechanisms of critical velocities has proven the most dramatic aspects of the superfluid state. a valuable test of our understanding of the nature The study of the limits of stable superflow and of the superfluid state for both superconductors 1332

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Heat flow in superfluid 3He

Cited by 85 publications

References 17 publications

Shear viscosity of superfluid 3He–A1 at low temperatures

Shear viscosity of superfluid 3He–A1 at low temperatures

Dissipation in the Flow ofHe3-Aand
Dahm
¹
,
Betts
²
,
Brewer
³

et al. 1980
Phys. Rev. Lett.
62
1
9
0
View full text Add to dashboard Cite

Critical Velocities in SuperfluidHe3

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Heat flow in superfluid 3He

Cited by 85 publications

References 17 publications

Shear viscosity of superfluid 3He–A1 at low temperatures

Shear viscosity of superfluid 3He–A1 at low temperatures

Dissipation in the Flow ofHe3-AandDahm1, Betts2, Brewer3 et al. 1980Phys. Rev. Lett.62190View full textAdd to dashboardCite

Critical Velocities in SuperfluidHe3

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Dissipation in the Flow ofHe3-Aand
Dahm
¹
,
Betts
²
,
Brewer
³

et al. 1980
Phys. Rev. Lett.
62
1
9
0
View full text Add to dashboard Cite