Superfluid Avalanches in Nuclepore: Constrained versus Free-Boundary Experiments and Simulations

Area of Science:

• Condensed Matter Physics
• Soft Matter Physics
• Nanotechnology

Background:

• Superfluid helium-4 (4He) exhibits unique quantum properties.
• Capillary condensation in nanoporous materials leads to hysteretic behavior.
• Avalanche phenomena are observed during the draining of fluids from porous media.

Purpose of the Study:

• To investigate the hysteretic behavior of superfluid 4He in Nuclepore.
• To understand the dependence of avalanche dynamics on fluid flow conditions during pore draining.
• To simulate and compare experimental observations of superfluid 4He draining.

Main Methods:

• Experimental observation of superfluid 4He filling and draining in Nuclepore.
• Analysis of avalanche size and frequency under impeded and unimpeded flow conditions.
• Computational simulation of superfluid 4He draining with pore meniscus perturbation.

Main Results:

• Superfluid 4He demonstrates hysteretic behavior and avalanches in Nuclepore.
• Avalanche characteristics are sensitive to whether fluid flow is impeded or unimpeded.
• Simulations successfully replicate experimental findings regarding flow inhibition effects.

Conclusions:

• Capillary condensation drives hysteretic behavior and avalanches in superfluid 4He within nanoporous materials.
• Flow conditions significantly influence avalanche dynamics during pore draining.
• Simulations provide a valuable tool for understanding complex fluid behavior in nanoporous systems.