Negative-Ion Capture by Vortex Lines in Helium II

1966 ◽  
Vol 152 (1) ◽  
pp. 121-128 ◽  
Author(s):  
D. J. Tanner
Keyword(s):  
Negative Ion ◽  
Helium Ii ◽  
Vortex Lines

Capture Width of Vortex Lines for Negative Ions in Helium II

1966 ◽  
Vol 141 (1) ◽  
pp. 192-197 ◽  
Author(s):  
R. L. Douglass
Keyword(s):  
Negative Ions ◽  
Helium Ii ◽  
Vortex Lines

Nonlinear Taylor–Couette flow of helium II

1995 ◽  
Vol 283 ◽  
pp. 329-340 ◽  
Author(s):  
Karen L. Henderson ◽  
Carlo F. Barenghi ◽  
Chris A. Jones
Keyword(s):  
Couette Flow ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Second Sound ◽  
Helium Ii ◽  
Vortex Lines ◽  
Taylor Couette ◽  
First Time ◽  
Two Fluid ◽  
Taylor Couette Flow

We solve the nonlinear two-fluid Hall–Vinen–Bekharevich–Khalatnikov equations of motion of helium II for the first time and investigate the configuration of quantized vortex lines in Taylor–Couette flow. The results are interpreted in terms of quantities which can be observed by measuring the attenuation of second sound. Comparison is made with existing experimental results.

Growth of Pinned Quantized Vortex Lines in Helium II

1966 ◽  
Vol 141 (1) ◽  
pp. 208-210 ◽  
Author(s):  
W. I. Glaberson ◽  
R. J. Donnelly
Keyword(s):  
Quantized Vortex ◽  
Helium Ii ◽  
Vortex Lines

Pressure Dependence of the Radius of the Negative Ion in Helium II

1966 ◽  
Vol 17 (7) ◽  
pp. 364-367 ◽  
Author(s):  
B. E. Springett ◽  
R. J. Donnelly
Keyword(s):  
Pressure Dependence ◽  
Negative Ion ◽  
Helium Ii

The behaviour of vortex lines near a wire in liquid helium II

1964 ◽  
Vol 277 (1369) ◽  
pp. 214-236 ◽  
Keyword(s):  
Vortex Core ◽  
Vortex Line ◽  
Core Radius ◽  
Potential Barriers ◽  
Helium Ii ◽  
Upper Limit ◽  
Vortex Lines ◽  
Large Vortex ◽  
The Wire ◽  
The Stability

By the application of classical hydrodynamics to the interaction between a wire and a parallel vortex line it is shown that states having different numbers of quanta of superfluid circulation about the wire are separated by high potential barriers. Possible ways of overcoming or avoiding the barriers are discussed, and it is concluded that such states are normally metastable. A method for finding steady vortex-line configurations is then developed, and it is found that, in an apparatus of the type used by Vinen (1961 b ) to detect single quanta of circulation, states having vortex lines partly attached to the wire are metastable in certain circumstances. These results are compared with Vinen’s account of his experiment. They agree well with the observations made when the apparatus had ceased to rotate. During rotation some points remain puzzling, but the failure to attain equilibrium, ascribed by Vinen to an anomalously large vortex core, is now seen to arise from the trapping of vortex lines in metastable states. A critical superfluid velocity of about 10 3 cm/s for the creation of vortex lines at a solid surface is derived, and, from this and the experimental observation of the stability of integral circulation about the wire against vibration, an upper limit of 3 x 10 -6 cm to the vortex core radius is tentatively deduced. It is concluded that the theory of quantized vortex lines of small (≈ 10 -7 cm) core radius can account fairly well for the observations. Further possible tests of the theory are suggested.

Vortex lines in liquid helium II

Physica ◽  
1958 ◽  
Vol 24 ◽  
pp. S13-S17 ◽  
Author(s):  
W.F. Vinen
Keyword(s):  
Liquid Helium ◽  
Helium Ii ◽  
Vortex Lines

Influence of an Axial Heat Current on Negative-Ion Trapping in Rotating Helium II

1973 ◽  
Vol 31 (7) ◽  
pp. 433-436 ◽  
Author(s):  
D. K. Cheng ◽  
M. W. Cromar ◽  
R. J. Donnelly
Keyword(s):  
Ion Trapping ◽  
Negative Ion ◽  
Heat Current ◽  
Helium Ii ◽  
Axial Heat

Stochastic theory of the interaction of ions and quantized vortices in helium II

1969 ◽  
Vol 312 (1511) ◽  
pp. 519-551 ◽  
Keyword(s):  
Potential Barrier ◽  
Vortex Line ◽  
Brownian Particle ◽  
Stochastic Theory ◽  
Planck Equation ◽  
Quantized Vortices ◽  
Two Dimensional ◽  
Potential Well ◽  
Helium Ii ◽  
Vortex Lines

The interaction of ions and quantized vortex lines in helium II is treated by imagining that the motion of the superfluid near a vortex line acts on an ion so as to produce a potential well. The ion itself is looked upon as a Brownian particle immersed in a gas of quasi-particles. The capture of ions is pictured as a process of sedimentation into the well. The escape of the ions from the well is treated as a problem of the escape of a Brownian particle over a potential barrier. A solution of the Fokker-Planck equation for a two-dimensional well is given. Comparison of the theory with a variety of experiments is presented.

The detection of single quanta of circulation in liquid helium II

1961 ◽  
Vol 260 (1301) ◽  
pp. 218-236 ◽  
Keyword(s):  
Liquid Helium ◽  
Present Form ◽  
Quantized Vortices ◽  
Free Vortex ◽  
Helium Ii ◽  
Vortex Lines ◽  
Fine Wire ◽  
The Wire ◽  
Λ Point ◽  
Made In

An apparatus is described for detecting single quanta of superfluid circulation round a fine wire in liquid helium II. The wire is stretched down the centre of a cylindrical vessel containing helium, and the circulation may be established by rotating the whole apparatus about the axis of the wire and cooling from above the λ-point. The wire can be set into transverse vibration, and the circulation round it can then be obtained from the rate of precession of the plane of vibration. The technique proves to be sufficiently sensitive for the measurement of circulations of order h/m with an accuracy of about 3%. The method in its present form measures only an average of the circulation along the length of the wire, and it is found that this average is not quantized. Apparent circulations equal to a fraction of a quantum are attributed to quantized vortices that are attached to only a fraction of the length of the wire, and this interpretation has been confirmed by showing that an apparent circulation of exactly h/m has much greater stability than any other value. In this way the quantization of superfluid circulation in units of h/m has been experimentally verified. Observations made in the course of this work show clearly that superfluid circulations (including free vortex lines) can persist indefinitely even when the rotation of the apparatus is stopped. Values have also been obtained for the circulation round the wire as a function of the angular velocity of rotation, and it is shown from these that the energy of a free vortex line in the helium surrounding the wire may perhaps be considerably smaller than has hitherto been supposed.

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