Production of enhanced pressure regions due to inhomogeneities in inertialconfinement fusion targets

It is shown that regions of enhanced pressure have been produced in targets with indirect radiation drive in planar and cylindrically convergent geome try through the interaction between the flows caused by target inhomogeneit ies and the main target drive. Design calculations for National Ignition Fa cility (NIF) [J. A. Paisner et al., Laser Focus World 30, 75 (1994)] target s with beryllium ablators formed by bonded hemi-shells [D. C. Wilson et al. , Bull. Am. Phys. Soc. 43, 1667 (1998)] indicate that related behavior prod uces a seed perturbation in the ablator which can in some cases lead to the suppression of ignition. From simulation and analysis of the NIF problem i n the planar geometry analog, a scaling for the perturbation, which should be useful for validation of the behavior with lower energy drive and smalle r-scale geometries, is derived. (C) 2000 American Institute of Physics. [S1 070-664X(00)94005-9].