Laser direct drive: Scientific advances, technical achievements, and the path to fusion power

Summary form only given. A family of simulations from several institutions shows the potential of Laser Direct Drive to provide the high gains needed for an attractive power plant based on pure fusion energy.1 Conventional designs show gains of 140 at laser energies of 2.4 MJ. Designs that exploit the deeper UV of a KrF laser show energy class gains (> 100) at 1 to 2 MJ. Shock Ignition designs offer the prospect of energy class gains with laser energies below 1 MJ. Shock Ignition, first proposed by the University of Rochester,2 has gains similar to Fast Ignition, but uses the simpler direct drive configuration without need for a separate multi-petawatt laser or complex targets. Using these designs we are developing the scientific and technical basis for laser fusion. We have a multi-disciplinary, multi-institutional program in which the key parts are developed together, coupling the science, technology, and fusion application. Advances have been made in all areas: two lasers (the Diode Pumped Solid State Laser, and electron beam pumped KrF gas laser), and the technologies applicable to both: final optics (grazing incidence and dielectrics); chambers, and target fabrication, injection and tracking. We have a three phase plan to take the current research to fusion power. Phase I develops full scale components: a laser beam line, target factory and injector, and chamber technologies. Phase II is a 5 Hz Fusion Test Facility (FTF).2 This could follow single shot ignition on the NIF. The FTF would have a -500 kJ laser and based on KrF targets could produce ~ 100 MW of fusion power. It would optimize the target physics and demonstrate integration. It would also be used to validate materials and sub modules in a fusion environment. Phase III would be a demonstration power plant based on the FTF, and would probably be led by industry.