Sudden diffusion of turbulent mixing layers in weakly coupled plasmas under compression.

The rapid growth of viscosity driven by temperature increase in turbulent plasmas under compression induces a sudden dissipation of kinetic energy, eventually leading to the relaminarization of the flow [Davidovits and Fisch, Phys. Rev. Lett 116, 105004 (2016)]. The interdiffusion between species is also greatly enhanced, so that mixing layers appearing at interfaces between different materials are subjected to strong dynamical modifications. The result is a competition between the vanishing turbulent diffusion and the expanding plasma microscopic diffusion. In direct numerical simulations with conditions relevant to inertial confinement fusion, we evidence regimes where compressed spherical mixing layers are quickly diffused during the relaminarization process. Using one and two-point turbulent statistics, we also detail how mixing heterogeneities are smoothed out.