Bradley, Ian and Fear, Matthew and Fisher, Shaun and Guénault, Tony and Haley, Richard and Lawson, Christopher and Pickett, George and Schanen, Roch and Tsepelin, Viktor and Wheatland, Louise (2014) Hysteresis, switching and anomalous behaviour of a quartz tuning fork in superfluid 4He. Journal of Low Temperature Physics, 175 (1-2). pp. 379-384. ISSN 0022-2291
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Abstract
We have been studying the behaviour of commercial quartz tuning forks immersed in superfluid 4He and driven at resonance. For one of the forks we have observed hysteresis and switching between linear and non-linear damping regimes at temperatures below 10 mK. We associate linear damping with pure potential flow around the prongs of the fork, and non-linear damping with the production of vortex lines in a turbulent regime. At appropriate prong velocities, we have observed metastability of both the linear and the turbulent flow states, and a region of intermittency where the flow switched back and forth between each state. For the same fork, we have also observed anomalous behaviour in the linear regime, with large excursions in both damping, resonant frequency, and the tip velocity as a function of driving force.