Rotationally induced dissipation in superfluid helium

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.9865· OSTI ID:5911992

Bonaldi, M; Vitale, S ^[1]; Cerdonio, M ^[2]

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1. Dipartimento di Fisica, Universita degli Studi di Trento, I-38050 Povo, Trento (Italy) Gruppo di Trento, Istituto Nazionale di Fisica Nucleare, I-38050 Povo, Trento (Italy)
2. Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, I-35020 Legnaro, Padova (Italy)

In an attempt to make a superfluid {sup 4}He analog of the radio-frequency superconducting quantum interference device (SQUID) that could be used as a gyroscope, we measured the critical velocity of the ac superflow through an orifice 5 {mu}m in radius. The orifice was supported by a septum placed inside a hollow torus filled with liquid helium. The superflow through the orifice was induced by rotating the whole torus. The torus was the inertial member of a high-quality-factor torsion pendulum forced to oscillate at its resonance frequency. The occurrence of dissipation was detected by analyzing the oscillator motion. The principle on which this device works is analyzed, and results are reported of experiments in which quite reproducible critical oscillation amplitudes---well accounted for by intrinsic vortex formation---were obtained. Depending on the value of the forcing torque, the critical behavior manifested itself either as the occurrence of sudden collapses of the oscillation amplitude or as a steady excess dissipation. The energy involved in the process was estimated. Temperature dependencies of the critical amplitude up to 2.115{plus minus}0.003 K were measured. The results were found to be in agreement both with the ac data obtained with the Helmholtz-resonator technique and with the data obtained with dc flow measurements.

• OSTI ID: 5911992
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:16; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CLOSED PLASMA DEVICES
COMPACT TORUS
DISSIPATION FACTOR
ELECTRONIC EQUIPMENT
EQUIPMENT
EVEN-EVEN NUCLEI
FLUID FLOW
FLUIDS
FLUXMETERS
GYROSCOPES
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LAMBDA POINT
LIGHT NUCLEI
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
NUCLEI
PHYSICAL PROPERTIES
QUANTUM FLUIDS
RF SYSTEMS
SQUID DEVICES
STABLE ISOTOPES
SUPERCONDUCTING DEVICES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
THERMONUCLEAR DEVICES
TORI
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE
VORTEX FLOW