Energy efficiency of laser greenhouse target for a small number of irradiating beams

Abstract

Targets of the "Laser Greenhouse" (GH) type are very promising ones for direct laser compression. The key feature of this type of targets is the presence of a layer of low-density volume structured medium, which surrounds a thermonuclear cell and acts as the laser radiation absorber. Some methods to achieve highly symmetrical compression of these targets by small (e.g. two) number of laser beams (or beam clusters) have been presented earlier. Simulations of compression of targets for total laser pulse energy of 100 kJ and 2.1 MJ have proved, that this type of targets allows one to achieve combustion and effective burn. In the paper we introduce the results of 2D simulations of some processes, which are specific to this design of targets. The attention is paid to the problem of symmetry of compression. We also have performed calculations of neutron yield of the target designed for compression by two beams with full energy of 2.6 kJ, and series of 2D simulations to model some microscopic processes in the absorber. The experiments on compression of the targets at energy level of 2.6 kJ can be performed on a number of present laser installations.