The implosion of spherical-shell targets driven ablatively by six 1.05-μm laser beams at an irradiance of ∼ ${10}^{13}$ W ${\mathrm{cm}}^{-2\mathrm{}}$ has been studied by streak time-resolved x-ray shadowgraphy. Measurements of acceleration determined the ablation pressure. Departures from one-dimensional simulations showed increasingly degraded implosions as the shell aspect ratio $\frac{\mathcal{r}}{\Delta \mathcal{r}}$ was increased from 10 to 110 for shells with surface perturbations of $\pm 0.05\Delta \mathcal{r}$.

• Received 30 July 1980

DOI:https://doi.org/10.1103/PhysRevLett.45.1801