Superfluid Turbulence in the Kelvin Wave Cascade Regime

TL;DR

This paper explores superfluid turbulence at very low temperatures, demonstrating that the energy spectrum follows Kolmogorov scaling, and investigates how spatial intermittency affects vortex dynamics and turbulence decay.

Contribution

It introduces a Hamiltonian framework for vortex line decay and incorporates fractal intermittency effects, providing new insights into turbulence behavior at small scales.

Findings

Energy spectrum aligns with Kolmogorov scaling.

Intermittency enhances vortex line density and decay.

Steepens energy spectrum consistent with experiments.

Abstract

Theoretical considerations are made of superfluid turbulence in the Kelvin wave cascade regime at low temperatures (T < 1K) and length scales of the order or smaller than the intervortical distance. The energy spectrum is shown to be in accord with the Kolmogorov scaling. The vortex line decay equation is shown to have an underlying Hamiltonian framework. Effects of spatial intermittency (exhibited in laboratory experiments) on superfluid turbulence are incorporated via the fractal nature of the vortex lines, for length scales of the order or smaller than the intervortical distance. The spatial intermittency effects are shown to enhance the vortex line density L, for a given value of intervortex spacing L, and to provide for a mechanism commensurate with the enhanced depolarization of vortex lines. The spatial intermittency is found to steepen the energy spectrum in qualitative agreement with laboratory experiments and to enhance vortex line decay.