Symmetrising effect of an x-ray prepulse in laser target compression

Two-dimensional numerical calculations were made in a study of the symmetrising effect of an x-ray prepulse on the inhomogeneity of laser target compression. It is suggested that a two-stage target, with its outer stage formed by a thin metal layer, can be used to generate such a prepulse. Correct selection of the parameters of this layer and of a laser prepulse can ensure symmetrisation of the inner working target with minimal undesirable preheating of the fuel. Such a target is accelerated and compressed at the expense of the energy of the main laser pulse. The influence of a large-scale asymmetry of irradiation, associated with a specific geometry of the radiation reaching the target, may be reduced by a suitable variation of the shell thickness.