Rotating Superfluid Turbulence

TL;DR

This paper investigates the complex vortex states in superfluid helium II under combined rotation and thermal counterflow, revealing a new steady state with polarized vortex tangles and explaining an observed instability.

Contribution

It introduces a numerical study of vortex behavior combining rotation and counterflow, uncovering a novel polarized vortex tangle state and explaining an existing experimental instability.

Findings

Discovery of a new steady state with polarized vortex tangles

Explanation of an experimentally observed instability

Numerical modeling of vortex dynamics under combined effects

Abstract

Almost all studies of vortex states in helium II have been concerned with either ordered vortex lattices or disordered vortex tangles. This work studies numerically what happens in the presence of both rotation (which induces order) and thermal counterflow (which induces disorder). We find a new statistically steady state in which the vortex tangle is polarized along the rotational axis. Our results are used to interpret an instability which was discovered experimentally by Swanson et al. years ago but has been unexplained until now.