Implosion hydrodynamics of an inertial confinement fusion target

We consider the hydrodynamic behaviour of an imploding ICF target. After,re calling the requirements for thermonuclear ignition, we analyse in detail t he two phases of the implosion. First, the acceleration, with its two impor tant ignition parameters, the implosion velocity and the entropy generated in the DT Second the slowing down which, through electronic conduction, all ows the creation of a central hot spot of sufficient mass. The method of su ccessive shocks allows the determination of the laser pulse shape which, by insuring an isentropic acceleration, optimises the energy delivered to the DT We obtain the implosion velocity as a function of the initial capsule p arameters and the maximum incident radiation. We clarify the hydrodynamical reason which makes the ignition threshold sensitive to the entropy generat ed during the acceleration. These elements constitute the basis of a global indirect drive ICF model, allowing target design optimisation. (C) 2000 Ac ademie des sciences/Editions scientifiques et medicales Elsevier SAS.