RESUMO
The interaction of a very intense, very short laser pulse is modified by the presence of a preformed plasma prior to the main short pulse. The preformed plasma is created by a small prepulse interacting with the target prior to the main pulse. The prepulse has been monitored using a water-cell-protected fast photodiode allowing on every shot a high dynamic measurement of the pulse profile. Simultaneously we have used time-resolved interferometry to look at the preformed plasma on a 300 TW, 700 fs laser. The two-dimensional density maps obtained have been compared with two-dimensional hydrodynamic simulations.
RESUMO
We have used spherically bent quartz crystal to image a laser-generated shock in a foam medium. The foam targets had a density of 0.16 g/cm(3) and thickness of 150 microm, an aluminum/copper pusher drove the shock. The experiment was performed at the Titan facility at Lawrence Livermore National Laboratory using a 2 ns, 250 J laser pulse to compress the foam target, and a short pulse (10 ps, 350 J) to generate a bright Ti K alpha x-ray source at 4.5 keV to radiograph the shocked target. The crystal used gives a high resolution (approximately 20 microm) monochromatic image of the shock compressed foam.
