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Séminaire MCBT : lundi 24 avril 2023 à 14h00


Jere Mäkinen (Dpt of Applied Physics, Aalto University, Finland)


Titre : Rotating quantum wave turbulence and onset of the Kelvin wave cascade


Institut Néel, Salle E424 (Louis Weil)
Résumé : Rotating turbulence in classical fluids can often be described as an ensemble of interacting inertial waves across a wide range of length scales. For turbulence in superfluids, the nature of the transition between the quasiclassical dynamics at large scales and the corresponding dynamics at small scales, where the quantization of vorticity is essential, remains an unresolved question. Based on our experiments in rotating superfluid helium-3 we expand the paradigm of wave-driven turbulence to rotating quantum fluids [1] where the spectrum of waves extends to microscopic scales as Kelvin waves on quantized vortices. We excite inertial waves at the largest scale by periodic modulation of the angular velocity and observe dissipation-independent transfer of energy to smaller scales and the eventual onset of the Kelvin-wave cascade at the lowest temperatures. We further find that energy is pumped to the system through a boundary layer distinct from the classical Ekman layer. We uncover a new regime of turbulent motion in quantum fluids where the role of vortex reconnections can be neglected, simplifying the transition between the classical and the quantum regimes of turbulence.

[1] Mäkinen, J.T. et al., Rotating quantum wave turbulence, Nat. Phys. (2023), https://doi.org/10.1038/s41567-023-01966-z