Fast-ignition target design and experimental-concept validation on OMEGA

A comprehensive scientific program is being pursued at LLE to explore the physics of fast ignition. The OMEGA EP Laser was completed in April 2008, adjacent to the 60 beam, 30 kJ OMEGA Laser Facility. OMEGA EP consists of four beamlines with a NIF-like architecture, each delivering up to 6.5 kJ of UV laser energy in long pulse (ns) mode into the OMEGA EP target chamber. Two of the beamlines can operate as high-energy petawatt lasers, with up to 2.6 kJ each with 10 ps pulse duration. These beams can either be injected into the OMEGA EP target chamber or combined collinearly into the existing OMEGA target chamber for integrated fast-ignitor experiments. Fuel-assembly experiments on OMEGA have achieved high fuel areal densities, and the effects of a cone on the fuel assembly are being studied. Experiments on short-pulse laser systems in collaboration with other institutions are being pursued to investigate the conversion efficiency from laser energy to fast electrons. A coherent transition radiation diagnostic to study the transport of the electrons in high-density material is being developed. Integrated experiments with room-temperature targets on OMEGA will be performed in 2008. Simulations of these integrated experiments show significant heating of up to 1 keV due to the hot electrons from the short-pulse laser. © 2008 IOP Publishing Ltd