Inter-vortex spacing in superfluid turbulence: temperature and Reynolds number dependences

International audienceThe typical spacing between superfluid vortices in an isothermal turbulent tangle is proportional to the integral scale H rescaled by the quantum Reynolds number Reκ = H · V · κ −1 to the power of 3/4, where κ is the quantum of circulation around of single vortex [1]. This empirical relation can be seen as the quantum-turbulence version of the corresponding well-know equation giving Kolmogorov dissipative scale in classical turbulence. In 2014, we studied the temperature dependence of the numerical factor δ/H × Re 3/4 κ in 4 He by joint numerical and experimental analysis of steady state turbulence over a wide temperature interval (1.2-2.16 K) [2]. Agreement between the two analyses was found good except at the very ends of this temperature interval. We will discuss this issue by presenting additional experimental data obtained by post-processing of superfluid experiments published between 1975 and 1998 [3, 4, 5]