Issue
EPL
Volume 81, Number 3, February 2008
Article Number 36002
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/81/36002
Published online 03 January 2008
EPL, 81 (2008) 36002
DOI: 10.1209/0295-5075/81/36002

Vortex spectrum in superfluid turbulence: Interpretation of a recent experiment

P.-E. Roche1 and C. F. Barenghi2

1  Institut NÉEL, CNRS/UJF - BP166, F-38042 Grenoble Cedex 9, France
2  School of Mathematics, University of Newcastle - Newcastle upon Tyne, NE1 7RU, UK


received 4 September 2007; accepted in final form 30 November 2007; published February 2008
published online 3 January 2008

Abstract
We discuss a recent experiment in which the spectrum of the vortex line density fluctuations has been measured in superfluid turbulence. The observed frequency dependence of the spectrum, f -5/3, disagrees with classical vorticity spectra if, following the literature, the vortex line density is interpreted as a measure of the vorticity or enstrophy. We argue that the disagrement is solved if the vortex line density field is decomposed into a polarised field (which carries most of the energy) and an isotropic field (which is responsible for the spectrum).

PACS
67.40.Vs - Vortices and turbulence.
47.37.+q - Hydrodynamic aspects of superfluidity: quantum fluids.
67.57.De - Quantum fluids and solids; liquid and solid helium: Superflow and hydrodynamics.

© EPLA 2008