Laser implosion of microballoons: study of the transition from exploding-pusher to ablative regime

Microballoons filled with an equimolar deuterium-tritium mixture and coated with a plastic ablator of variable thickness are imploded by the eight-beam Octal laser (λ = 1.06 μm; 0.6 TW). An X-ray diagnostic with space-time resolution is used to analyse the implosion of the targets designed to the highest ∫ ρdr. The experimental results are compared with numerical simulations performed by a one-dimensional Lagrangian code. A DT density of about 2 g·cm −3 is obtained; the transition from an exploding-pusher regime to a more ablative one is analysed on the basis of the evolution of the preheat, the hydrodynamic efficiency and the density and temperature performance.