Decay of superfluid turbulence via Kelvin wave radiation and vortex reconnections

TL;DR

This paper investigates how superfluid turbulence decays at low temperatures through vortex ring collisions, Kelvin wave radiation, and reconnections, highlighting the limited role of sound emission in the decay process.

Contribution

It provides a detailed numerical analysis of vortex interactions and identifies Kelvin wave radiation as a key decay mechanism in superfluid turbulence.

Findings

Small vortex rings are annihilated in collisions, converting energy into Kelvin waves and sound.

Sound emission from Kelvin waves contributes to vortex line length loss but is insufficient alone for observed decay.

Kelvin wave radiation plays a significant role in the decay of superfluid turbulence.

Abstract

The elementary processes involved in the decay of superfluid turbulence in the limit of low temperature are studied by numerical simulations of vortex ring collisions. We find that small vortex rings produced by reconnections eventually annihilate in a collision where all their energy is converted into Kelvin waves and sound. We show that sound emission due to Kelvin waves also leads to a loss of vortex line length but this dissipation mechanism alone is too small to account for the experimentally observed decay.