Mesoscale helicity distinguishes Vinen from Kolmogorov turbulence in helium II

TL;DR

This paper introduces a mesoscale helicity measure for superfluid helium II that effectively differentiates between Kolmogorov and Vinen turbulence regimes by quantifying vortex interactions and orientations.

Contribution

It proposes a novel mesoscale helicity metric that distinguishes turbulence types in helium II, supported by numerical experiments.

Findings

Mesoscale helicity effectively differentiates turbulence regimes.

Vinen turbulence shows lower mesoscale helicity than Kolmogorov turbulence.

The measure quantifies nonlocal vortex interactions and vortex line orientations.

Abstract

Experiments and numerical simulations show that quantum turbulence exists in two distinct limiting regimes: Kolmogorov turbulence (which shares with classical turbulence the important property of a cascade of kinetic energy from large eddies to small eddies) and Vinen turbulence (which is more similar to a random flow). In this work, we define a mesoscale helicity for the superfluid, which, tested in numerical experiments, distinguishes the two turbulent regimes, quantifying the amount of nonlocal vortex interactions and the orientation of the vortex lines.