Shock-wave-driven instability at material interface in laser driven implosion

Material mixing induced by hydrodynamic instability in the implosion process is the most important issue in studying implosion processes in inertial confinement fusion (ICF). We have studied the elementary process of the Richtmyer-Meshkov instability driven at an uneven material inter-face, when a shock wave passes through it. The second-order Godunov scheme is adopted to study the generation of vortices, mushroom formation and triple point generation on the surface of the transmitted shock wave. Results of detailed studies on why the interface is unstable regardless of the density ratio across the material interface are described. In addition, the rippling of the transmitted shock wave is explained relative to the up-and-down motion of the triple point.