[en] Interaction of light ions beams with various targets is calculated from an ion energy deposition model coupled with an hydrodynamic code, taking account of the plasma evolution during the target heating. The calculations are made in two cases: at low power densities available on a laboratory machine as SIDONIX, at high power densities required for pellet fusion. In the case of low power densities the requirements of a neutron target implosion experiment are discussed. The simulation of deposition processes at high power densities shows that the energy deposition characteristics are strongly modified during the target heating

[en] Implosion experiments performed at Centre d'Etudes de Limeil-Valenton in the indirect drive scheme using the two-beams Nd glass laser facility Phebus at the energy level ≅ 6 kJ (blue light) are presented. A final density of compressed DT close to 100 ρ₀ has been obtained. Phebus has also been equipped with an optical fibre oscillator, to study the effect of a smoothing technique on coupling processes: at 0.53 μm, absorption efficiency is increased by ≅15-20%. With the eight beams Octal laser, hydrodynamic instabilities development in accelerated planar targets has been investigated both for direct and indirect drive. Atomic physics in laser plasmas is also deeply studied; a particular effort has been made on absorption spectroscopy which is a powerful diagnostic of ionization dynamics in cold and dense plasmas. In order to reach fuel ignition conditions, much powerful lasers, in the range of megajoule, will be needed. Their design needs further technological developments in order to reduce the capital cost. At Limeil, we work mainly on high damage threshold optical coatings, using the sol-gel process, high quality - low cost mirror fabrication, using the replica technics and incoherent laser pulse generation for beam smoothing

[en] The principal objective of the CEL-V laser program is to realize high performances ablative implosions. The indirect drive approach has been chosen to reach the high degree of uniformity required. In relation to this objective, the radiation transfer and the development of hydrodynamics instabilities are widely studied. Besides, efforts have been developed in the field of diagnostics, and of laser technology with optical smoothing and high damage level coatings studies

[en] A time-related study of relativistic-electron-beam (REB) interactions, with thin targets, 5 μm gold and 75 and 6 μm mylar, was carried out from experimental data on anode and cathode voltage and transmitted current. REB absorption by a thin target is reflected by a variable drop in transmitted current. The use of a code to simulate the slowing of electrons in the material serves to show that for the nearest possible voltage and current input parameters, no significant difference is observed between REB--5-μm-gold-target and REB--75-μm-mylar-target interaction. However, a current transmission defect was observed with the thinner mylar films

[en] In accordance with the principal objective of the laser programme of the Centre d'Etudes de Limeil-Valenton, which is to realize high performance implosions, radiative transfer and hydrodynamic instabilities are widely studied. In relation to this objective, efforts have been made in the field of diagnostics for accurate measurements on ablative implosions. Work is also being done to improve the beam quality using either distributed phase plates or an optical fibre oscillator. The effects of optical smoothing on X ray conversion and ablation depth are presented. (author). 12 refs, 7 figs