Richtmyer-Meshkov instability with strong radiatively driven shocks

The Richtmyer-Meshkov instability is investigated with strong radiatively driven shocks (Mach>20, 5Xcompression) using the Nova laser. The target consists of a solid density ablator and lower-density plastics (Atwood number A<0) in planar geometry to facilitate in-flight radiographic diagnosis. Perturbations eta=eta(0) cos kx are imposed at the interface to seed the instability. The experiments agree with full hydrodynamic simulations over a wide variety of conditions. For small initial amplitudes \A\k eta(0)<1, the growth rate agrees with a linear impulsive model using the average of the pre- and post-shock initial amplitudes. For \A\k eta(0)>1, the growth rate is limited to the difference between the transmitted shock speed and the interface speed. (C) 1996 American Institute of Physics.