First indirect drive Inertial Confinement Fusion Campaign on Laser Megajoule

This study concerns the first ICF experiments on the LMJ facility in the indirect drive scheme. Approximately 150 kJ of laser energy was distributed on 48 beams (12 quads) arranged in two cones. The target consisted of a gold vacuum rugby shaped hohlraum and a plastic capsule located at its center, filled with deuterium gas fuel. With 12 quads, the laser irradiation on the wall generated a three-dimensional (3D) x-radiation flux around the capsule creating 3D deformations on the plastic shell. This constraint forced the design of a robust target (relatively thin ablator, around 40 µm) with a short laser pulse (3 ns). Full-integrated 3D simulations with the radiation-hydrodynamics code TROLL permitted at the same time to build targets and to interpret data (mainly radiation temperature, x-ray images and neutron yield). A good agreement was reached between 3D calculations and experiments, especially for the number of neutrons, which was about 10¹¹.