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Experiments on a high quality grid oscillating in superfluid 4He at very low temperatures.

Research output: Contribution to journalJournal article

Published

Journal publication date02/2010
JournalJournal of Low Temperature Physics
Journal number3-4
Volume158
Number of pages6
Pages462-467
Original languageEnglish

Abstract

We have investigated a copper-mesh grid oscillating at its fundamental (0, 1) Bessel mode in superfluid 4He for temperatures 10< T <1500 mK at a pressure of P = 5 bar. The high quality factor (Q ∼ 10 to power 5) of the oscillator allowed us to observe new features of its response to a periodic drive which, at the lowest T, was found to depend on the prehistory of the helium. The experiments have confirmed the existence of two critical velocities, and we discuss whether these critical velocities are associated with quantized vortices.