Rights statement: Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Published by the American Physical Society
Final published version, 1.57 MB, PDF document
Available under license: CC BY
Final published version
Licence: CC BY
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Article number | 214503 |
---|---|
<mark>Journal publication date</mark> | 9/06/2014 |
<mark>Journal</mark> | Physical review B |
Issue number | 21 |
Volume | 89 |
Number of pages | 9 |
Publication Status | Published |
<mark>Original language</mark> | English |
We have studied the transition between pure potential flow and turbulent flow around a quartz tuning fork resonator in superfluid He-4 at millikelvin temperatures. Turbulent flow is identified by an additional drag force on the fork prongs due to the creation of quantized vortices. When driven at a constant driving force amplitude, the transition to turbulence causes an abrupt decrease in the velocity amplitude of the prongs. For a range of driving forces, continuous switching is observed between the two flow states. We have made a statistical study of the switching characteristics and of the lifetimes of the unstable states. We find a characteristic velocity nu(star) which separates quasistable turbulent flow at higher velocities and quasistable potential flow at lower velocities. We show that the potential-to-turbulent flow transition is driven by random processes involving remanent vortices pinned to the prongs.