Measurements of turbulent mixing due to Kelvin–Helmholtz instability in high-energy-density plasmas

• Published in: High energy density physics Vol. 9; no. 1; pp. 47 - 51
• Main Authors: Smalyuk, V.A., Hurricane, O.A., Hansen, J.F., Langstaff, G., Martinez, D., Park, H.-S., Raman, K., Remington, B.A., Robey, H.F., Schilling, O., Wallace, R., Elbaz, Y., Shimony, A., Shvarts, D., Di Stefano, C., Drake, R.P., Marion, D., Krauland, C.M., Kuranz, C.C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2013
• Subjects: Hydrodynamic instabilities; Hydrodynamic instabilities
• ISSN: 1574-1818; 1878-0563
• DOI: 10.1016/j.hedp.2012.10.001

Kelvin–Helmholtz (KH) turbulent mixing measurements were performed in experiments on the OMEGA Laser Facility [T.R. Boehly et al., Opt. Commun. 133 (1997) 495]. In these experiments, laser-driven shock waves propagated through low-density plastic foam placed on top of a higher-density plastic foil. Behind the shock front, lower-density foam plasma flowed over the higher-density plastic plasma. The interface between the foam and plastic was KH unstable. The experiments were performed with pre-imposed, sinusoidal 2D perturbations, and broadband 3D perturbations due to surface roughness at the interface between the plastic and foam. KH instability growth was measured using X-ray, point-projection radiography. The mixing layer caused by the KH instability with layer width up to ∼100 μm was observed at a location ∼1 mm behind the shock front. The measured mixing layer width was in good agreement with simulations using a K–L turbulent mixing model in the two-dimensional ARES hydrodynamics code. In the definition of the K–L model K stands for the specific turbulent kinetic (K) energy, and L for the scale length (L) of the turbulence.