Thermal flux of quasiparticles and the transition between two regimes of turbulence in He3-B

TL;DR

This paper investigates how the arrangement of vortices in superfluid helium-3 B affects the thermal quasiparticle flux, revealing a transition between turbulence regimes and aligning with experimental observations.

Contribution

It introduces a detailed computation of Andreev reflection coefficients for different vortex configurations, highlighting the impact of vortex pairing on turbulence regimes.

Findings

Reflection coefficient is significantly lower for paired vortex points.

Vortex pairing corresponds to a vortex ring gas, reducing turbulence.

Results align with experimental measurements by Bradley et al.

Abstract

We compute the Andreev reflection coefficient of a flux of thermal quasiparticles in He3-B incident upon various two-dimensional vortex configurations. We find that, for the same number of positive and negative vortex points, the reflection coefficient is much reduced if the points are arranged in pairs (which corresponds to a gas of vortex rings in three-dimensions) rather than random (which corresponds to a vortex tangle in three-dimensions). This results is consistent with measurements performed by Bradley et al. at the University of Lancaster.