Physical Review Letters

Vortex-Ring Creation by Negative Ions in Dilute Mixtures of He3 - He4

George W. Rayfield

Published Jun 24, 1968• 51 citations

Abstract

We describe an experiment which indicates that the addition of ${\mathrm{He}}^{3}$ impurities to superfluid helium has a pronounced effect on the velocity at which negative ions produce vorticity (vortex rings). The ${\mathrm{He}}^{3}$ impurities have no effect, however, on the creation of vorticity by positive ions.

DOI: 10.1103/physrevlett.20.1467

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Evidence for Two Vortex-Ring Species in Dilute He3 - He4 Solutions

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Physical Review Letters

Vortex-Ring Creation by Negative Ions in Dilute Mixtures of He3 - He4

George W. Rayfield

Published Jun 24, 1968• 51 citations

Publisher

Abstract

We describe an experiment which indicates that the addition of

{\mathrm{He}}^{3}

impurities to superfluid helium has a pronounced effect on the velocity at which negative ions produce vorticity (vortex rings). The

{\mathrm{He}}^{3}

impurities have no effect, however, on the creation of vorticity by positive ions.

DOI: 10.1103/physrevlett.20.1467

Related papers

Evidence for Two Vortex-Ring Species in Dilute He3 - He4 Solutions

Moyses Kuchnir, John B. Ketterson, Pat R. Roach

Measurements of the positive-ion velocity as a function of electric field in dilute solutions of $^{3}\mathrm{He}$ in $^{4}\mathrm{He}$ at 18 mK show a discontinuity which suggests the existence of two kinds of vortex rings in addition to the bare ion. The assignment of circulation quantum numbers is discussed.Measurements of the positive-ion velocity as a function of electric field in dilute solutions of $^{3}\mathrm{He}$ in $^{4}\mathrm{He}$ at 18 mK show a discontinuity which suggests the existence of two kinds of vortex rings in addition to the bare ion. The assignment of circulation quantum numbers is discussed.

Physical Review LettersApr 12, 19715 citations

Effect of He3 Impurities on the Lifetime of Ions Trapped on Quantized Vortex Lines

Gary A. Williams, R. E. Packard

The lifetimes of both positive and negative ions trapped on quantized vortex lines in rotating $^{3}\mathrm{He}$ - $^{4}\mathrm{He}$ mixtures have been measured at temperatures down to 0.1 K. Evidence is found that the $^{3}\mathrm{He}$ condenses at the vortex core, and possibly at the surface of the electron bubble.The lifetimes of both positive and negative ions trapped on quantized vortex lines in rotating $^{3}\mathrm{He}$-$^{4}\mathrm{He}$ mixtures have been measured at temperatures down to 0.1 K. Evidence is found that the $^{3}\mathrm{He}$ condenses at the vortex core, and possibly at the surface of the electron bubble.

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We have produced and observed quantized vortex rings emitted from orifices when superfluid helium is forced through channels at critical velocity. The vortices are identified by measuring their velocity and size, and are found to be in the $n=1$ quantum state.We have produced and observed quantized vortex rings emitted from orifices when superfluid helium is forced through channels at critical velocity. The vortices are identified by measuring their velocity and size, and are found to be in the $n=1$ quantum state.

Physical Review LettersAug 20, 197333 citations

Charged-Vortex-Ring Creation by Ions in Superfluid Helium

S. Cunsolo, B. Maraviglia

Physical ReviewNov 5, 196946 citations

Evolution of a Pulse of Charged Vortex Rings in Superfluid Helium

George Gamota, Akira Hasegawa, C. M. Varma

Physical Review LettersApr 19, 197142 citations

We describe an experiment which indicates that the addition of

{\mathrm{He}}^{3}

impurities to superfluid helium has a pronounced effect on the velocity at which negative ions produce vorticity (vortex rings). The

{\mathrm{He}}^{3}

impurities have no effect, however, on the creation of vorticity by positive ions.

Measurements of the positive-ion velocity as a function of electric field in dilute solutions of

^{3}\mathrm{He}

^{4}\mathrm{He}

at 18 mK show a discontinuity which suggests the existence of two kinds of vortex rings in addition to the bare ion. The assignment of circulation quantum numbers is discussed.

The lifetimes of both positive and negative ions trapped on quantized vortex lines in rotating

^{3}\mathrm{He}

^{4}\mathrm{He}

mixtures have been measured at temperatures down to 0.1 K. Evidence is found that the

^{3}\mathrm{He}

condenses at the vortex core, and possibly at the surface of the electron bubble.

Measurements of the velocity of charge carriers in several dilute solutions of

^{3}\mathrm{He}

^{4}\mathrm{He}

in the temperature range 0.017-1.0 K are reported. The low-field negative-ion mobility shows a ${T}^{\ensuremath{-}\frac{1}{2}}$ dependence below 0.08 K characteristic of hard-sphere scattering. A maximum is observed in the mobility in the vicinity of 0.4 K. This can be interpreted in terms of a

^{3}\mathrm{He}

condensation on the bubble surface. The positive-ion mobility is nearly temperature independent below 0.7 K. This has recently been interpreted in terms of a momentum-dependent polarization scattering. The field dependence of the positive-carrier velocity shows a discontinuity in the vortex-ring regime. The discontinuity can be shown to result from a size-dependent drag coefficient and a maximum is observed for very small rings (\ensuremath{\sim}16 \AA{}).

n=1

quantum state.