We present experimental, numerical, and theoretical studies of a vortex front propagating into a region of vortex-free flow of rotating superfluid ${}^3\mathrm{He}\mathrm{\text{−}}B$. We show that the nature of the front changes from laminar through quasiclassical turbulent to quantum turbulent with decreasing temperature. Our experiment provides the first direct measurement of the dissipation rate in turbulent vortex dynamics of ${}^3\mathrm{He}\mathrm{\text{−}}B$ and demonstrates that the dissipation becomes mutual-friction independent with decreasing temperature, and it is strongly suppressed when the Kelvin-wave cascade on vortex lines is predicted to be involved in the turbulent energy transfer to smaller length scales.

• Received 8 August 2007

DOI:https://doi.org/10.1103/PhysRevLett.99.265301