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Tsubota, Makoto; Ogawa, Shin Ichiro; Hattori, Yuji

doi:10.1023/a:1017562016052

Cited by 8 publications

(4 citation statements)

References 7 publications

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“…The former reduces to the Euler vortex filament model when variations of the wave function over scales of the order of the superfluid healing length are neglected. The GP equation includes such complicated compressible effects as the radiation of sound from the vortex lines [6,7], the vortexsound interactions, etc. In order to consider the intrinsic property of superfluid turbulence in a simpler situation, we study the energy spectrum of the 3D velocity field induced by the vortex tangle in the absence of the normal fluid under the vortex filament model.…”

mentioning

confidence: 99%

Energy Spectrum of Superfluid Turbulence with No Normal-Fluid Component

Araki¹,

Tsubota²,

Nemirovskii³

2002

Phys. Rev. Lett.

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181

178

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The energy spectrum of the superfluid turbulence without the normal fluid is studied numerically under the vortex filament model. Time evolution of the Taylor-Green vortex is calculated under the full nonlocal Biot-Savart law. It is shown that for k < 2π/l, the energy spectrum is very similar to the Kolmogorov's -5/3 law which is the most important statistical property of the conventional turbulence, where k is the wave number of the Fourier component of the velocity field and l the average intervortex spacing. The vortex length distribution becomes to obey a scaling property reflecting the self-similarity of the tangle. 67.40.Vs, 67.40.Bz Particular attention has been focused recently on the similarity between superfluid turbulence and conventional turbulence [1][2][3]. Early work of the superfluid turbulence has been concerned with the counterflow where the normal fluid and superfluid flow oppositely [4], having no classical analog. However Stalp et al. studied recently the superfluid turbulence produced by the towed grid, thus finding the similarity between the superfluid turbulence and the conventional turbulence above 1.4 K [2]. They observed indirectly the Kolmogorov law which is one of the most important statistical properties of the conventional turbulence. This is understood by the idea that the superfluid and the normal fluid are likely to be coupled together by the mutual friction between them, and to behave like a conventional fluid [1,5]. Since the normal fluid is negligible at mK temperatures, an important question arises: even free from the normal fluid, is the superfluid turbulence still similar to the conventional turbulence or not?As the physical model to describe the vortex dynamics in superfluid He at very low temperatures, two types of models are well-known: the Gross-Pitaevskii (GP) equation which describes the motion of a weakly interacting Bose condensate, and the vortex filament model governed by the incompressible Euler dynamics. The former reduces to the Euler vortex filament model when variations of the wave function over scales of the order of the superfluid healing length are neglected. The GP equation includes such complicated compressible effects as the radiation of sound from the vortex lines [6,7], the vortexsound interactions, etc. In order to consider the intrinsic property of superfluid turbulence in a simpler situation, we study the energy spectrum of the 3D velocity field induced by the vortex tangle in the absence of the normal fluid under the vortex filament model.The energy spectrum of the vortices in superfluid was numerically calculated by other authors. Nore et al. studied the energy spectrum of the decaying superfluid turbulence by using the GP equation, and finding the transient spectrum for small k has the Kolmogorov law [3]. However at late stage some complicated compressible effects become dominant. On the other hand, an advantage of the vortex filament model compared with the GP equation is the followings. First this model enables us to calculate the energy s...

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mentioning

confidence: 99%

Energy Spectrum of Superfluid Turbulence with No Normal-Fluid Component

Araki¹,

Tsubota²,

Nemirovskii³

2002

Phys. Rev. Lett.

Self Cite

181

178

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“…A useful tool to study vortexsound interactions is the Gross-Pitaevskii (GP) equation. Although unable to fully represent the physics of HeII, the GP equation does provide a sophisticated fluid dynamical model capable of describing vortex nucleation [5] and reconnections [6][7][8]. Furthermore, the GP equation has been shown to provide an accurate description of the recently discovered atomic Bose-Einstein condensates [9], where similar issues of vortex-sound interactions are likely to occur, particularly in experiments where many vortices are formed [10,11].…”

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confidence: 99%

Sound Emission due to Superfluid Vortex Reconnections

et al. 2001

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“…Being generated, vortices can be distributed in many directions, first, without actually forming a tangled configuration. When the finite size of the cloud is saturated with the vortices, any further pumped energy forces a fast evolution of the vortices, promoting their reactions by reconnections [132], eventually yielding a turbulent cloud. At this stage, not only the distribution of the vortices is an indication for the occurrence of turbulence, but also a change in the hydrodynamic behavior, during the free expansion of the cloud, works as the indicator of turbulence.…”

Section: Amplitude-time Phase Diagrammentioning

confidence: 99%

From Coherent Modes to Turbulence and Granulation of Trapped Gases

Bagnato¹,

Yukalov²

2012

Progress in Optical Science and Photonics

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The process of exciting the gas of trapped bosons from an equilibrium initial state to strongly nonequilibrium states is described as a procedure of symmetry restoration caused by external perturbations. Initially, the trapped gas is cooled down to such low temperatures, when practically all atoms are in Bose-Einstein condensed state, which implies the broken global gauge symmetry. Excitations are realized either by imposing external alternating fields, modulating the trapping potential and shaking the cloud of trapped atoms, or it can be done by varying atomic interactions by means of Feshbach resonance techniques. Gradually increasing the amount of energy pumped into the system, which is realized either by strengthening the modulation amplitude or by increasing the excitation time, produces a series of nonequilibrium states, with the growing fraction of atoms for which the gauge symmetry is restored. In this way, the initial equilibrium system, with the broken gauge symmetry and all atoms condensed, can be excited to the state, where all atoms are in the normal state, with completely restored gauge symmetry. In this process, the system, starting from the regular superfluid state, passes through the states of vortex superfluid, turbulent superfluid, heterophase granular fluid, to the state of normal chaotic fluid in turbulent regime. Both theoretical and experimental studies are presented.Comment: Latex file, 25 pages, 4 figure

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Cited by 8 publications

References 7 publications

Energy Spectrum of Superfluid Turbulence with No Normal-Fluid Component

Energy Spectrum of Superfluid Turbulence with No Normal-Fluid Component

Sound Emission due to Superfluid Vortex Reconnections

From Coherent Modes to Turbulence and Granulation of Trapped Gases

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