Design and performance of future KrF laser-fusion facilities

The US inertial confinement fusion program is investigating the feasibility of constructing a high-gain laboratory microfusion facility (LMF). Considerable uncertainties and risks exist for all the driver candidates in proceeding directly to this facility without an intermediate step. The risks fall into the categories of driver performance and cost, target physics, and target chamber performance. Los Alamos has developed a plan to resolve these issues before construction of the LMF. The plan calls for the construction of an LMF prototype beamline at the 100-kJ energy level and the parallel development of a large (240-kJ) KrF amplitude module. The prototype facility, called the Laser Target Test Facility (LTTF), will address target physics issues at the 100-kJ level and will demonstrate the performance and cost scaling of KrF lasers. Along with this construction, a 240-kJ LMF amplifier module will also be developed. After successful operation of the LTTF for a period of about two years, and construction and operation of the LMF amplifier module, all driver issues will be satisfactorily resolved. If sufficient understanding of target physics extrapolations is realized from this facility, the LMF can then be constructed with acceptable risk. If an additional step is needed for understanding target physics and capsule ignition, the LTTF can be upgraded to an energy level on target of 1-3 MJ. This upgrade would provide a direct test of LMF-scale laser and optic hardware and would provide much information on the function of the LMF target chamber. The construction of a 3-MJ KrF facility could be an LMF if high target gains are achieved with shaped broadband KrF laser pulses. >