The CEA’s Military Applications Division (DAM) is responsible for the design, manufacture, through-life support and dismantling of the nuclear warheads that equip France’s sea- and airborne deterrence forces. Since 1996, France has relied on the Simulation Program to guarantee the operational performance and safety of its nuclear weapons throughout their lifetime. The program is based on a usual scientific approach that implies hundreds of scientists and major facilities for solving and validating the equations used to model the functioning of thermonuclear weapons: supercomputers (EXA1, DIF), X-ray machines (EPURE, Valduc) and the MegaJoule Laser (LMJ, CESTA).
The talk will open with an historical review of the development of the French nuclear deterrence that highlights the pioneering work of CEA’s teams of scientists. Since the definitive ending of nuclear tests, the DAM constantly streamlined its organizational structure: five main programs are currently managed in five military centers: nuclear warheads, nuclear reactors for submarines and aircraft carriers, strategic materials, prevention of proliferation, conventional defence.
To meet the challenge of guaranteeing the reliability of nuclear warheads under the Simulation Program, the Laser MegaJoule is a crucial tool for the experimental validation of the physical dynamics involved in the nuclear phase of weapon functioning. Once fully commissioned, 176 laser beams will deliver a maximum power of 400 TW of UV light on the target. Among all experiments, Inertial Confinement Fusion (ICF) sets the most stringent specifications on LMJ’s features, as the aim is to initiate nuclear fusion reactions by compressing and heating targets filled with a Deuterium-Tritium fuel. To measure the different phenomena, the LMJ presently offers several diagnostics operating in multiple X-visible-UV wavelengths ranges as well as particles diagnostics. The last part of the talk will be dedicated to one of these plasma diagnostics: the near-backscatter imaging (NBI) system. The NBI measures the stimulated Brillouin and Raman scattered light around two laser quads of the upper LMJ hemisphere and contributes to the estimation of energy balance.
Coffee and pastries will be served at 11:00 in the hall.