Sub-scale shock-ignition studies on OMEGA

The shock ignition (SI) scheme [1] for inertial confinement fusion offers the potential of high gain at relatively low driver energy compared to standard hot-spot approaches. SI designs are imploded at lower velocity and include a high-intensity laser spike at the end to drive a strong spherical shock into the capsule, resulting in higher hot-spot pressures at capsule stagnation time. Previous experiments [2] on the OMEGA Laser using room-temperature capsules showed improved yield by a factor of four over a standard hot-spot reference design; however, attempts to field SI on cryogenic capsules resulted in poor performance due largely to low spike laser power and shock pressure. Recent developments on OMEGA, including a multi-pulse driver (MPD) and new phase plates for smaller laser spots, now allow for more optimal SI implosions. Higher spike intensities are anticipated with more rapid rise-to-spike times. Here we will present simulations and preliminary results from OMEGA experiments.



[1] R. Betti, et al., Phys. Rev. Lett. 98, 155001 (2007).

[2] W. Theobald, et al., Phys. Plasmas 15, 056306 (2008).