Time-of-Flight Experiments of Vortex Rings Propagating from Turbulent Region of Superfluid 4He at High Temperature

• Published in: Journal of low temperature physics Vol. 162; no. 3-4; pp. 322 - 328
• Main Authors: Nago, Y., Ogawa, T., Obara, K., Yano, H., Ishikawa, O., Hata, T.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.02.2011
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Fluid dynamics; Fluid flow; Fluids; Magnetic Materials; Magnetism; Physics; Physics and Astronomy; Turbulence; Turbulent flow; Vortex rings; Vortices; Wire; Quantized vortex; Quantum turbulence; Superfluid helium; Oscillatory flow
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/s10909-010-0277-1

We report the time-of-flight of quantized vortex rings generated by a vibrating wire in superfluid 4 He which contains normal fluid component. A cover box of vibrating wires and slow cooling of superfluid reduce the number of vortices attached to wire surfaces, enabling us to study vortex rings propagating from a turbulent region. Using two vibrating wires as a generator and a detector of vortices, the time-of-flight of vortices propagating a distance of 0.88 mm was measured at 1.25 K. We find that the time-of-flights distribute from 0.06 s to 27.4 s, much larger than the lifetimes of circular vortex rings limited in the size of a generator amplitude. These results imply that large vortex rings with non-circular shape or vortex tangles are created by the generator, propagating slowly and colliding with the detector before complete disappearance.