CONTRIBUTIONS OF THE NATIONAL IGNITION FACILITY TO THE DEVELOPMENT OFINERTIAL FUSION ENERGY

The US Department of Energy is proposing tdo construct the National Ig nition Facility (NIF) to embark on a program to achieve ignition and m odest gain in the laboratory early in the next century. The NIF will u se a greater than or equal to 1.8 MJ, 0.35 mu m laser with 192 indepen dent beams, a 50-fold increase over the energy of the Nova laser. Syst em performance analyses suggest yields as great as 20 MJ may be achiev able. NIF will conduct more than 600 shots per year. The benefits of a micro-fusion capability in the laboratory include essential contribut ions to defence programs, resolution of important Inertial Fusion Ener gy (IFE) issues and unparalleled conditions of energy density for basi c science and technology research. A start has been made to consider t he role the NIF will fill in the development of IFE. While the achieve ment of ignition and gain speaks for itself in terms of its impact on developing IFE, it is believed there are areas of IFE development, suc h as fusion power technology, IFE target design and fabrication and un derstanding chamber dynamics, that would significantly benefit from NI F experiments. In the area of IFE target physics, ion targets will be designed using the NIF laser and the feasibility of high-gain targets will be confirmed. Target chamber dynamics experiments will benefit fr om X-ray and debris energies that mimic the spatial distribution of ne utron heating, activation and tritium breeding in relevant materials. IFE target systems will benefit from evaluating low-cost target fabric ation techniques by testing such targets on NIF. Additionally, it is b elieved that it is feasible to inject up to four targets and engage th em with the MF laser by triggering the beams in groups of ca. 50 separ ated in time by ca. 0.1 s. Sub-ignition neutron yields would allow an indication of symmetry achieved in such proof-of-principle rep-rate ex periments. NIF will be a unique source of data to benchmark predictive capabilities to support affordable IFE technology selections. The tot al of NIF-IFE experiments may involve several thousands of shots. NIF may support design ''certification'' for the follow-on facility to NIF , dedicated to IFE, called the Engineering Test Facility.