Coherent structure formation in turbulent thermal superfluids.

Area of Science:

• Quantum fluid dynamics
• Turbulence theory
• Condensed matter physics

Background:

• Superfluidity involves quantum phenomena in fluids at low temperatures.
• Turbulence in superfluids presents unique challenges due to quantized vortices.
• Understanding the interaction between normal and superfluid components is crucial.

Purpose of the Study:

• To investigate the formation and dynamics of quantized vortices induced by a normal fluid in a turbulent superfluid.
• To analyze the spectral properties and energy transfer mechanisms of these induced vortices.
• To develop a theoretical framework for the statistical mechanics of this system.

Main Methods:

• Numerical simulations of turbulent thermal superfluids.
• Analysis of vortex dynamics, including circulation and stretching.
• Spectral analysis of vortex structures and energy transfer.
• Development of a statistical mechanics model.

Main Results:

• Coherent bundles of quantized line vortices are induced in the superfluid by the normal fluid.
• These filamentary structures form between normal fluid vortices and exhibit self-regulating dynamics.
• The vortex spectrum mimics the normal fluid spectrum, with mutual friction affecting large and small scales.
• Sporadic merging of vortex triads leads to stronger, braided filaments and energetic fluctuations.

Conclusions:

• The normal fluid plays a key role in organizing superfluid vorticity.
• The dynamics of induced vortices are characterized by self-regulation and scale-dependent interactions.
• The findings provide insights into the complex interplay of turbulence and quantum phenomena in superfluids.
• A theoretical framework for the system's statistical mechanics is proposed.