Separation of Micron-Scale Particles by Size Using Helium II

Fuzier, Sylvie; Kalechofsky, N.; Sciver, S.W. Van

doi:10.1007/s10909-008-9817-3

Cited by 2 publications

(1 citation statement)

References 16 publications

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“…Jin and Maris (2011) describes some interesting behavior of dust particles in superfluid helium, and La Mantia et al (2012) confirms that hydrogen particle velocities equal the normal fluid velocity at low heat fluxes. Fuzier et al (2008) shows that superfluid helium can be used to segregate particles by size. Guo et al (2009) images electron bubbles and speculates that this technique could be used to track quantized vortices.…”

Section: B Recent Historymentioning

confidence: 99%

The journey of hydrogen to quantized vortex cores

Bewley

Vollmer

2013

Phys. Scr.

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Nanoscale hydrogen particles in superfluid helium track the motions of quantized vortices. This provides a way to visualize turbulence in the superfluid. Here, we trace the evolution of the hydrogen from a gas to frozen particles migrating toward the cores of quantized vortices. Not only are the intervening processes interesting in their own right, but understanding them better leads to more revealing experiments.

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Section: B Recent Historymentioning

confidence: 99%

The journey of hydrogen to quantized vortex cores

Bewley

Vollmer

2013

Phys. Scr.

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Sub-micron solid air tracers for quantum vortices and liquid helium flows

Fonda

Sreenivasan

Lathrop

2016

Review of Scientific Instruments

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The dynamics of quantized vortices in superfluids has received increased attention recently because of novel techniques developed to visualize them directly. One of these techniques [G. P. Bewley et al., Nature 441, 588 (2006)] visualized quantized vortices and their reconnections in superfluid flows of (4)He by using solid hydrogen tracers of micron-size or larger. The present work improves upon the previous technique by using substantially smaller particles created by injecting atmospheric air diluted in helium gas. These smaller particles are detectable thanks to the higher index of refraction of nitrogen compared to hydrogen and thanks to an improved visualization setup. The optical counting estimate, which agrees with terminal velocity estimates, suggests that the tracer diameter is typically 400 ± 200 nm and could be as small as 200 nm; being smaller, but not so small as to be influenced by thermal motion, the particles get trapped on the vortices faster, perturb the vortices less, possess smaller Stokes drag, and stay trapped on fast-moving vortices, as also on vortices generated closer to the superfluid transition temperature. Unlike the past, the ability to create particles in the superfluid state directly (instead of creating them above the λ-point and cooling the fluid subsequently), ensures greater temperature stability for longer periods, and enables the tracking of long and isolated vortices. These advantages have also led to the direct visualization of Kelvin waves. The use of other seed gases could lead to the visualization of even smaller tracers for quantized vortices. We discuss the visualization setup and provide suggestions for further improvement.

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Separation of Micron-Scale Particles by Size Using Helium II

Cited by 2 publications

References 16 publications

The journey of hydrogen to quantized vortex cores

The journey of hydrogen to quantized vortex cores

Sub-micron solid air tracers for quantum vortices and liquid helium flows

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