摘要 :
Vortex dynamics is used to consider the following problems concerning vortices in the space between concentric spheres: the equilibrium shape of vortices (they are almost rectilinear if their number is large), the metastable clust...
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Vortex dynamics is used to consider the following problems concerning vortices in the space between concentric spheres: the equilibrium shape of vortices (they are almost rectilinear if their number is large), the metastable clusters with nonequilibrium number of vortices, the processes of vortex breaking and connection in the vicinity of the inner sphere equator, the annihilation in the vicinity of the outer sphere equator, and the behavior of an almost freely rotating double-sphere device during the variation of the superfluid angular momentum caused by the changes of vortex configuration (similar phenomena are among the possible reasons of pulsars self-acceleration).
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摘要 :
Vortex dynamics is used to consider the following problems concerning vortices in the space between concentric spheres: the equilibrium shape of vortices (they are almost rectilinear if their number is large), the metastable clust...
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Vortex dynamics is used to consider the following problems concerning vortices in the space between concentric spheres: the equilibrium shape of vortices (they are almost rectilinear if their number is large), the metastable clusters with nonequilibrium number of vortices, the processes of vortex breaking and connection in the vicinity of the inner sphere equator, the annihilation in the vicinity of the outer sphere equator, and the behavior of an almost freely rotating double-sphere device during the variation of the superfluid angular momentum caused by the changes of vortex configuration (similar phenomena are among the possible reasons of pulsars self-acceleration).
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The thermal activation or quantum tunneling is believed to be necessary for the vortex nucleated near a wall to escape from its vicinity, and for the vortex nucleated in the bulk to reach the critical size above which it can incre...
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The thermal activation or quantum tunneling is believed to be necessary for the vortex nucleated near a wall to escape from its vicinity, and for the vortex nucleated in the bulk to reach the critical size above which it can increase according to its own dynamics. This paper suggests the idea that there exists the possibility to understand these processes (without leaving the framework of hydrodynamics) as the result of the simultaneous presence of several vortices or the interaction between various sections of vortex lines.
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摘要 :
The critical velocity of the first vortex generation in a superfluid confined to the space between two rotating concentric spheres as well as the width of an irrotational area and the equilibrium number of vortices are determined.
摘要 :
The critical velocity of the first vortex generation in a superfluid confined to the space between two rotating concentric spheres as well as the width of an irrotational area and the equilibrium number of vortices are determined.
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Using the equations of vortex dynamics the waves on a vortex ring are studied both analytically and by computer simulations. At small amplitudes the results coincide. The dispersion relations and the expressions of phase and group...
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Using the equations of vortex dynamics the waves on a vortex ring are studied both analytically and by computer simulations. At small amplitudes the results coincide. The dispersion relations and the expressions of phase and group velocities are determined. The free and forced oscillations are considered. At large amplitudes the shape of a vortex is strongly distorted and the ring motion changes its direction. The second approximation calculations and computer simulations agree in order of magnitude.
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The proximity effect is responsible for the existence of a transition region with graded variation of the superfluid component density instead of a sharp boundary at the level where the hydrostatic pressure induces a He II-He I ph...
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The proximity effect is responsible for the existence of a transition region with graded variation of the superfluid component density instead of a sharp boundary at the level where the hydrostatic pressure induces a He II-He I phase transition. Under microgravity the characteristic length of this effect increases and the conditions become more conducive for performing measurements in the transition region. The problem of expanding the thermodynamic potential in a power series near a He II-He I interface is considered. The critical size of the superfluid region is determined.
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摘要 :
Concentric spheres with radii R{sub}1 and R{sub}2 rotating with a constant or variable angular velocity ω are considered. Both equilibrium and metastable states of this system are solutions of the equations of vortex dynamics wit...
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Concentric spheres with radii R{sub}1 and R{sub}2 rotating with a constant or variable angular velocity ω are considered. Both equilibrium and metastable states of this system are solutions of the equations of vortex dynamics with a given velocity and zero mutual friction between the vortices and the normal component. This force brings about transitions from one equilibrium or metastable state to another upon a change of angular velocity. But there also exist such configurations of vortices which cannot stay stable even if the variation of the velocity of rotation is interrupted. In this publication of our report at CWS-2002 the part devoted to equilibrium and metastable rotation (see Ref. 1) is omitted. This paper is dedicated to the mechanism of the unstable processes and to the difference between double-cylinder and double-sphere devices.
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摘要 :
The proximity effect causes the existence of some transition area with the gradual variation of the density of superfluid component instead of the sharp boundary at the level where the hydrostatic pressure realizes the phase trans...
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The proximity effect causes the existence of some transition area with the gradual variation of the density of superfluid component instead of the sharp boundary at the level where the hydrostatic pressure realizes the phase transition He Ⅱ-He Ⅰ. In the microgravity environment the characteristic length of this effect increases, and more convenient conditions arise for measurements in the transition area. The problem of the expansion of thermodynamical potential in power series in the vicinity of He Ⅱ-He Ⅰ interface is considered. The critical values of the size of the superfluid area are determined.
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摘要 :
The unstable states (including those related to self-accelerations of pulsars) in which the mutual friction causes an irreversible motion of vortices is considered.
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