First we report two studies aimed at preparing laser integration line (LIL) experiments (LIL is the prototype of LMJ): deflection of a beam with and without ‘longitudinal’ smoothing (associated with focusing by gratings) and the radiation temperature, Tr, in a hohlraum with long pulses (10–20 ns). Experimentally, we did not see any Langmuir decay instability able to saturate the stimulated Raman scattering in a gas bag irradiated with the Omega laser. Next, in our hydro-code FCI2, we implemented an improved version of the non-LTE atomic physics model: the change in Tr in the hohlraum is negligible, but now the simulations are in agreement with experiments on x-ray conversion and on Rayleigh–Taylor instabilities (RTIs) in a spherical geometry. The RTIs in polyimide foil at 70 µm were understood, but not those at 30 µm. Finally, for the target design, we confirm the hydro-stability of the four targets of the operational domain of LMJ: the doped CH ablator of the nominal target can withstand a roughness in the range 50–100 nm. The robustness studies use 19 uncertainties coming from the laser power, the beam pointing and the target fabrication. Finally, the burning of DT has been studied in detail, identifying three regimes.

A weakly nonlinear model is proposed for the Rayleigh-Taylor instability in the presence of surface tension. The dynamics of a multimode perturbation of the interface between two incompressible, inviscid, irrotational, and immiscible fluids is analyzed. The quadratic and cubic nonlinear effects are taken into account. They include the nonlinear corrections to the exponential growths of the fundamental modulations. The role of the initial modulation spectrum is discussed. A saturation criterion in terms of the product of a local rms and a particular wave number is exhibited. It gives theoretical foundations for numerical conjectures and allows one to analyze the effects of fundamental parameters of the problem such as the dimension or the Atwood number.

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

Nonlocal heat transport is investigated under conditions relevant to laser-driven fusion. Results from the nonlocal transport model of Luciani and Mora are compared with results from Fokker–Planck codes and from local flux-limited diffusion simulations. No significant nonlocal effects are found in hydrodynamic simulations for irradiation with either 1.06 or 0.35 μm laser light. Over a large range of conditions, the transport is well modeled with a harmonic averaged flux-limiter between 0.1 and 0.2.