Vortex spectrum in superfluid turbulence: interpretation of a recent experiment

Philippe-Emmanuel Roche (1) , Carlo Barenghi (2)

1 NEEL - HELFA - Hélium : du fondamental aux applications
2 School of Mathematics and Statistics

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).

Mots clés: vortex; superfluid; quantum turbulence; vorticity; helium

Domaines: Autre [cond-mat.other]; Mécanique des fluides [physics.class-ph]; Dynamique des Fluides [physics.flu-dyn]; Mécanique des fluides [physics.class-ph]

Philippe-Emmanuel Roche, Carlo Barenghi. Vortex spectrum in superfluid turbulence: interpretation of a recent experiment. EPL - Europhysics Letters, 2008, 81, pp.36002. ⟨10.1209/0295-5075/81/36002⟩. ⟨hal-00169495⟩