The two-fluid theory and second sound in liquid helium

Physics Today ◽  
2009 ◽  
Vol 62 (10) ◽  
pp. 34-39 ◽  
Author(s):  
Russell J. Donnelly
Keyword(s):  
Liquid Helium ◽  
Second Sound ◽  
Fluid Theory ◽  
Two Fluid

scholarly journals Two Fluid Theory of Liquid Helium II. below 1 K

1951 ◽  
Vol 6 (1) ◽  
pp. 122-125 ◽  
Author(s):  
S. Nakajima ◽  
M. Shimizu
Keyword(s):  
Liquid Helium ◽  
Helium Ii ◽  
Fluid Theory ◽  
Two Fluid

The rotation of liquid helium II I. Experiments on the propagation of second sound in uniformly rotating helium II

1956 ◽  
Vol 238 (1213) ◽  
pp. 204-214 ◽  
Keyword(s):  
Liquid Helium ◽  
Fluid Model ◽  
Mutual Friction ◽  
Second Sound ◽  
Order Unity ◽  
Helium Ii ◽  
Axis Of Rotation ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Excess Attenuation

An experimental investigation of the propagation of second sound in uniformly rotating resonators filled with liquid helium II has been made. It is found that in the uniformly rotating liquid the velocity of the second sound is not changed by more than 0·1%, but there is an excess attenuation which is, except near the λ point, proportional to the angular velocity ω , independent of second-sound amplitude, and independent of frequency in the range 1·5 to 4·5 kc/s. These results are described phenomenologically by a mutual friction force B ( ρ s ρ n / ρ ) ω (v s — v n ) per unit volume in the two-fluid model. The constant B is of order unity for second sound propagated at right angles to the axis of rotation; it is smaller by a factor of at least 5 when the second sound is propagated parallel to the axis of rotation. It is suggested that the mutual friction in rotating helium may contain a component perpendicular to (v s — v n ), and that there should be no mutual friction in an irrotational circulation. Experiments to verify these predictions are proposed.

Two-Fluid Theory of Liquid Helium II below 1°K

1950 ◽  
Vol 80 (5) ◽  
pp. 923-923 ◽  
Author(s):  
S. Nakajima ◽  
M. Shimizu
Keyword(s):  
Liquid Helium ◽  
Helium Ii ◽  
Fluid Theory ◽  
Two Fluid

scholarly journals Modelling of mirror mode structures as propagating slow magnetosonic solitons

2009 ◽  
Vol 27 (12) ◽  
pp. 4379-4389 ◽  
Author(s):  
K. Stasiewicz ◽  
C. Z. Cheng
Keyword(s):  
Numerical Modelling ◽  
Excellent Agreement ◽  
Plasma Flow ◽  
Numerical Solutions ◽  
Small Subset ◽  
Instability Condition ◽  
Magnetic Pulsations ◽  
Fluid Theory ◽  
Mirror Mode ◽  
Two Fluid

Abstract. Cluster measurements in the magnetosheath with spacecraft separations of 2000 km indicate that magnetic pulsations interpreted as mirror mode structures are not frozen in plasma flow, but do propagate with speeds of up to ~50 km/s. Properties of these pulsations are shown to be consistent with propagating slow magnetosonic solitons. By using nonlinear two fluid theory we demonstrate that the well known classical mirror instability condition corresponds to a small subset in a continuum of exponentially varying solutions. With the measured plasma moments we have determined parameters of the polybaric pressure model in the region of occurrence of mirror type structures and applied it to numerical modelling of these structures. In individual cases we obtain excellent agreement between observed mirror mode structures and numerical solutions for magnetosonic solitons.

Obliquely propagating generalized lower-hybrid drift instability with nonlocal two-fluid theory in current sheet equilibrium

2010 ◽  
Vol 17 (10) ◽  
pp. 102102 ◽  
Author(s):  
Dandan Zou ◽  
Weihong Yang ◽  
Yinhua Chen ◽  
P. H. Yoon
Keyword(s):  
Current Sheet ◽  
Lower Hybrid ◽  
Fluid Theory ◽  
Drift Instability ◽  
Two Fluid
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