Using second-sound shock waves to probe the intrinsic critical velocity of liquid helium II

1983 ◽  
Vol 26 (11) ◽  
pp. 3227 ◽  
Author(s):  
Timothy N. Turner
Keyword(s):  
Shock Waves ◽  
Liquid Helium ◽  
Critical Velocity ◽  
Second Sound ◽  
Helium Ii

Quantum hydrodynamics and the theory of liquid helium

1953 ◽  
Vol 219 (1137) ◽  
pp. 257-270 ◽  
Keyword(s):  
Energy Spectrum ◽  
Liquid Helium ◽  
Fluid Velocity ◽  
Second Sound ◽  
Quantum Hydrodynamics ◽  
Dynamical Equations ◽  
Helium Ii ◽  
Apparent Variation ◽  
Theory Of Fields ◽  
Good Agreement

The Clebsch formula, u = –∇ ϕ – χ ∇ ψ , for the fluid velocity allows the classical hydro-dynamical equations, including vorticity, to be derived from a variational principle, and put into canonical form. The standard quantization procedure of the theory of fields then gives a set of field operators satisfying the commutation relations obtained (starting from different premises) by Landau (1941). The Hamiltonian contains terms corresponding to the excitation of the ‘roton’ states of Landau’s theory, with an energy spectrum (allowing for the atomicity of real liquids by a ‘cut off’ in the Fourier analysis of the field variables) of the form E = ∆ + p 2 /2 μ . The observed variations of specific heat and second-sound velocity in liquid helium II may be interpreted to give values of ∆ in good agreement with the theory, with an apparent variation of μ with p , perhaps attributable to roton-roton and phonon-roton interactions.

Critical Velocity of Superflow in Liquid Helium II

1952 ◽  
Vol 85 (6) ◽  
pp. 1044-1045 ◽  
Author(s):  
H. M. Fried ◽  
P. R. Zilsel
Keyword(s):  
Liquid Helium ◽  
Critical Velocity ◽  
Helium Ii

Second Sound Attenuation in Liquid Helium II

1954 ◽  
Vol 95 (2) ◽  
pp. 321-327 ◽  
Author(s):  
W. B. Hanson ◽  
J. R. Pellam
Keyword(s):  
Liquid Helium ◽  
Sound Attenuation ◽  
Second Sound ◽  
Helium Ii

The angular acceleration of liquid helium II

1957 ◽  
Vol 250 (980) ◽  
pp. 359-385 ◽  
Keyword(s):  
Liquid Helium ◽  
Critical Velocity ◽  
Past History ◽  
Angular Acceleration ◽  
Mutual Friction ◽  
Helium Ii ◽  
Direct Measurements ◽  
History Of ◽  
Quantitative Results ◽  
Flow Experiments

Direct measurements have been made of the torques required to produce angular acceleration and retardation of liquid helium II contained in a can filled with closely spaced disks at a temperature of 1.27°K. The acceleration and retardation processes are not equivalent, and it is suggested that this asymmetry is due to the presence of vortex lines in the uniformly rotating superfluid. It is found that the forces producing superfluid acceleration are dependent on the past history of the helium and are greatly enhanced if the disk surfaces are roughened; furthermore, the superfluid flow shows a strong tendency to be macroscopically irrotational during retardation. These properties suggest that the forces are associated with turbulence in the superfluid, and it is found that a consistent description of the results can be given in terms of a mutual friction due to such turbulence. Values of the mutual friction appropriate to a steady flow are deduced and found to be in good agreement with values deduced from the results of other isothermal flow experiments; they can be represented, above a critical velocity, by a modification of the law introduced by Gorter & Mellink (1949), namely Fsn = A p sp n with A=23+/-2 posie -1 . V 0 =-0.6 +/- 0.2 c, s -1 Below the critical velocity a persistent current with a lifetime of at least 25 min has been observed. In the last section quantitative results on the growth and decay of turbulence in a non-equilibrium situation are presented, and laws describing the growth and decay processes are formulated.

Pulsed Second Sound in Liquid Helium II

1948 ◽  
Vol 74 (7) ◽  
pp. 841-841 ◽  
Author(s):  
J. R. Pellam
Keyword(s):  
Liquid Helium ◽  
Second Sound ◽  
Helium Ii

Second Sound Velocity in Paramagnetically Cooled Liquid Helium II

1949 ◽  
Vol 76 (6) ◽  
pp. 869-870 ◽  
Author(s):  
John R. Pellam ◽  
Russell B. Scott
Keyword(s):  
Sound Velocity ◽  
Liquid Helium ◽  
Second Sound ◽  
Helium Ii

Second Sound in Liquid Helium II

1947 ◽  
Vol 71 (9) ◽  
pp. 600-605 ◽  
Author(s):  
C. T. Lane ◽  
Henry A. Fairbank ◽  
William M. Fairbank
Keyword(s):  
Liquid Helium ◽  
Second Sound ◽  
Helium Ii

Mechanical Energy Density of Second Sound in Liquid Helium II

1967 ◽  
Vol 160 (1) ◽  
pp. 244-249 ◽  
Author(s):  
Claire D. Metz ◽  
Henry A. Boorse ◽  
Erna M. J. Herrey
Keyword(s):  
Energy Density ◽  
Liquid Helium ◽  
Mechanical Energy ◽  
Second Sound ◽  
Helium Ii
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