The effect of laser-beam spatial modulations on plane targets is analyzed as a function of modulation scale length and target material by means of x-ray shadowgraphy. At short laser wavelength it is shown that lateral energy smoothing is clearly improved because of the strong x-ray emission from the irradiated high-Z side of layered targets. The results, interpreted in terms of radiation-driven thermal transport, are in agreement with numerical simulations. PACS numbers: 52.50.Jm, 44.40. + a, 52.25.Fi, 52.55.Mg

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A time-resolved X-ray conversion efficiency campaign was conducted at CEA/Limeil–Valenton on the PHEBUS laser, with Au planar targets. The calibrated diagnostic DEMIXART has measured X-ray emissions driven by shaped laser pulses. The results have been analyzed with the “physicist” 1D1/2 hydrodynamical code CHIVAS, where improved transport coefficients have been implemented. The influence of the degeneracy and solid/liquid corrections on various parameters is shown. Other significant effects due to focal spot shapes and lateral conduction are quantified with the FCI2 hydroradiative code of CEA/DRIF.

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Velocities up to 108 cm s−1 have been obtained in laser implosion of gold-coated microballoons driven by irradiation at short wavelength. Despite a strongly nonuniform illumination, high neutron yield (i.e., high fuel temperature) has been obtained. Results analysis suggests that the glass shell is first decompressed by x-ray radiation from the gold coating and then accelerated by the ablation pressure.