2017/03/10 by P. M. Walmsley, A. I. Golov · 1 citation
Physics and Astronomy · #physics.flu-dyn #cond-mat.other
paper · pdf · doi:10.1103/physrevlett.118.134501
published as Phys. Rev. Lett. 118, 134501 (2017)
arxiv created 2017/03/10 · arxiv updated 2017/03/31
Tangles of quantized vortex line of initial density \cal L(0) ∼ 6× 103 cm-2 and variable amplitude of fluctuations of flow velocity U(0) at the largest length scale were generated in superfluid 4He at T=0.17 K, and their free decay \cal L(t) was measured. If U(0) is small, the excess random component of vortex line length firstly decays as \cal L ∝ t-1 until it becomes comparable with the structured component responsible for the classical velocity field, and the decay changes to \cal L ∝ t-3/2. The latter regime always ultimately prevails, provided the classical description of U holds. A quantitative model of coexisting cascades of quantum and classical energies describes all regimes of the decay.