Kinetics of a Network of Vortex Loops in He II and a Theory of Superfluid Turbulence

Abstract

A theory is developed to describe the superfluid turbulence on the base of kinetics of the merging and splitting vortex loops. Because of very frequent reconnections the vortex loops (as a whole) do not live long enough to perform any essential evolution due to the deterministic motion. On the contrary, they rapidly merge and split, and these random recombination processes prevail over other slower dynamic processes. To develop quantitative description we take the vortex loops to have a Brownian structure with the only degree of freedom, which is the length $l$ of the loop. We perform investigation on the base of the Boltzmann type kinetic equation for the distribution function $n(l)$ of number of loops with length $l$. By use of the special ansatz in the collision integral we have found the exact power-like solution to kinetic equation in the stationary case. This solution is not (thermodynamically) equilibrium, but on the contrary, it describes the state with two mutual fluxes of the length (or energy) in space of sizes of the vortex loops. The term flux means just redistribution of length (or energy) among the loops of different sizes due to reconnections. Analyzing this solution we drew several results on the structure and dynamics of the vortex tangle in the turbulent superfluid helium. In particular, we evaluated the mean radius of the curvature and the full rate of the reconnection events. We also studied the evolution of the full length of vortex loops per unit volume-the so-called vortex line density. It is shown this evolution to obey the famous Vinen equation. The properties of the Vinen equation from the point of view of the developed approach had been discussed.

arXiv comment34 pages, 9 Postscript figures, [aps,preprint,12pt]{revtex4}

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• Dynamics of vortex tangle without mutual friction in superfluid ${}^4$He
• The evolution of a network of cosmic string loops
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Cited by in corpus (10)

• Basics of Bose-Einstein Condensation
• Theory of decay of superfluid turbulence in the low-temperature limit
• Diffusion of Inhomogeneous Vortex Tangle and Decay of Superfluid Turbulence
• Thermally- and mechanically-driven quantum turbulence in helium II
• Reconnections of quantized vortex rings in superfluid ${}^4$He at very low temperatures
• Reconnection of vortex filaments and Kolmogorov spectrum
• Quantum turbulence and Planckian dissipation
• Fluctuations of the vortex line density in turbulent flows of quantum fluids
• Spectral energy distribution and generalized Wien's law for photons, cosmic string loops and related physical objects
• Probing of quantum turbulence with radiating vortex loops