Onset of turbulence in superfluid 3He-B and its dependence on vortex injection in applied flow

TL;DR

This paper investigates how vortex injection influences the transition to turbulence in superfluid 3He-B, revealing temperature-dependent dynamics and the impact of injection methods on turbulence onset.

Contribution

It provides experimental insights into the temperature-dependent vortex dynamics and the role of injection methods in the onset of turbulence in superfluid 3He-B.

Findings

Turbulence onset temperature depends exponentially on vortex friction.

Injection method affects the precise onset temperature.

High-temperature regime conserves vortex number, low-temperature regime involves vortex multiplication.

Abstract

Vortex dynamics in 3He-B is divided by the temperature dependent damping into a high-temperature regime, where the number of vortices is conserved, and a low-temperature regime, where rapid vortex multiplication takes place in a turbulent burst. We investigate experimentally the hydrodynamic transition between these two regimes by injecting seed vortex loops into vortex-free rotating flow. The onset temperature of turbulence is dominated by the roughly exponential temperature dependence of vortex friction, but its exact value is found to depend on the injection method.