Laser driven implosion of high aspect ratio spherical shell target

A simple model for the description of the ablative implosion of a thin spherical shell filled with fuel gas is presented. The model gives the fuel conditions before the beginning of the stagnation phase. Therefore, it can be applied to recent experiments producing a high neutron yield in which that phase was affected by instabilities. The model is compared with experiments, and scaling laws are found in agreement with the simulation and experimental results. (author)