Flow Phase Diagram for the Helium Superfluids

TL;DR

This paper establishes a flow phase diagram for helium superfluids He II and $^3$He-B, integrating experimental data and Volovik's theory to identify turbulent regimes and characterize flow states.

Contribution

It introduces a unified flow phase diagram based on an effective Reynolds number, linking experimental observations with theoretical predictions for helium superfluids.

Findings

Identification of turbulent states I and II in counterflowing He II.

Correlation of experimental data with Volovik's turbulence regimes.

Definition of a temperature-dependent, scale-independent Reynolds number.

Abstract

The flow phase diagram for He II and $^3$He-B is established and discussed based on available experimental data and the theory of Volovik [JETP Letters {\bf{78}} (2003) 553]. The effective temperature - dependent but scale - independent Reynolds number $Re_{eff}=1/q=(1+\alpha')/\alpha$, where $\alpha$ and $\alpha'$ are the mutual friction parameters and the superfluid Reynolds number characterizing the circulation of the superfluid component in units of the circulation quantum are used as the dynamic parameters. In particular, the flow diagram allows identification of experimentally observed turbulent states I and II in counterflowing He II with the turbulent regimes suggested by Volovik.