The nucleation of vortices in superfluid [sup 4]He: Answers and questions

Conference · Wed Dec 01 04:00:00 EST 1993 · Journal of Low Temperature Physics; (United States)

OSTI ID:5343993

Avenel, O; Ihas, G G ^[1]; Varoquaux, E ^[2]

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1. Centre d'Etudes de Saclay (France)
2. Universite Paris-Sud, Orsay (France)

The velocity threshold for phase slips, v[sub c], has been measured in ultra-pure [sup 4]He and ultra-dilute [sup 3]He-[sup 4]He mixtures, down to a temperature of 15 mK. These experiments have revealed a crossover from a temperature-dependent regime above [approximately]150 mK to a plateau of v[sub c] below in ultra-pure [sup 4]He. Concentrations of [sup 3]He impurities as low as a few parts in 10[sup [minus]9] greatly affect the plateau regime, causing v[sub c] to decrease markedly at low temperature. These observations are interpreted in the framework of the nucleation, either thermally activated or by quantum tunnelling, of vortices in the appropriate shape of half-rings. These vortices form on wall asperities at local velocities u[sub s] estimated to be [approximately]22 m/s in these experiments. The half-ring model is shown to yield a critical velocity of the same magnitude but leaves many basic questions unanswered.

• OSTI ID: 5343993
• Report Number(s): CONF-9308208--
• Conference Information: Journal Name: Journal of Low Temperature Physics; (United States) Journal Volume: 93:5-6
• Country of Publication: United States
• Language: English

Related Subjects

665420* -- Superfluidity-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BINARY MIXTURES
DISPERSIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
HELIUM 3
HELIUM 4
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MIXTURES
NUCLEATION
NUCLEI
STABLE ISOTOPES
VORTICES