Analysis of rippled shock-wave propagation and ablation-front stability bytheory and hydrodynamic simulation

The hydrodynamic start-up problem is one of the most crucial issues in lase r driven symmetrical implosion. The tar get-surface roughness and initial i mprint by nonuniform laser irradiation result in Rayleigh-Taylor instabilit y in the acceleration and deceleration phase. To estimate the tolerance of the target surface roughness, the temporal behaviour of corrugated ablation surface and rippled shock-wave propagation are investigated using a pertur bation analysis of the fluid equation, which is solved under the boundary m odel of a fire polished ablation surface. The results show good agreement w ith two-dimensional hydrodynamic simulation and experimental results [T. En do et al., Phys. Rev. Lett. 74, 3608 (1995)].