Energy and vorticity spectra in turbulent superfluid ⁴He from T=0 to T_λ

We discuss the energy and vorticity spectra of turbulent superfluid ⁴He in the entire temperature range from T=0 up to the phase transition "λ point," T_λ≃2.17K. Contrary to classical developed turbulence in which there are only two typical scales, i.e., the energy injection L and the dissipation scales η, here, the quantization of vorticity introduces two additional scales, the vortex core radius a0 and the mean vortex spacing ℓ. We present these spectra for the super- and the normal-fluid components in the entire range of scales from L to a₀ including the crossover scale ℓ where the hydrodynamic eddy cascade is replaced by the cascade of Kelvin waves on individual vortices. At this scale, a bottleneck accumulation of the energy was found earlier at T=0. We show that even very small mutual friction dramatically suppresses the bottleneck effect due to the dissipation of the Kelvin waves. Using our results for the spectra we estimate the Vinen "effective viscosity" ν′ in the entire temperature range and show agreement with numerous experimental observations for ν′(T).