Evolution of the target design for MJ laser

In the previous design, the maximum drive radiation temperature was 4 MK or 350 eV (Holstein 1996). Different beam configurations gave roughly the sam e uniformity with the NIF-size cavity. Our best configuration used four con es of beams illuminating three rings. An integrated 2D simulation pointed o ut that the symmetry was good enough to: reach a gain of ten. Two evolution s took place in the design of our MJ laser. We moved from a capsule adapted to 4 MK (L1000) to another one adapted to 3.5 MK (L1215) in order to minim ize the parametric instabilities (the cavity size is almost the same). This new capsule also has a better hydrostability according to the "classical m odelling" (Lindl 1995). The second evolution is a simplification of the tar get chamber. We restricted ourselves to two major configurations for indire ct drive (two-ring and three-ring configurations). Therefore, only three co nes of beams are necessary instead of five cones in the first design. Final ly, the number of holes in the chamber is 80 instead of 100.