Inertial Fusion Energy Target Designs using Low Velocity, High Mass Targets and Advanced Ignition Schemes

Focused Energy is pursuing inertial fusion energy using advanced ignition schemes --proton fast ignition and shock ignition -- using laser direct drive to drive a low velocity (~ 200 km/s), high mass (~ 2.5 mg DT) implosion.   The low implosion velocity has several advantages when compared to the high implosion velocities needed for central hotspot ignition:  the thick fuel layer results in a lower in-flight aspect ratio (IFAR), which is a measure of the hydrodynamic stability of the implosion to break up in-flight, increased robustness to low mode asymmetry, and higher target gain.  In addition, the lower velocity can result in reduced laser intensity and LPI risk.   The trade-off is that we need an alternate method to ignite these designs – we are considering proton fast ignition as well as shock ignition schemes.    In this talk, we will describe our current designs as well as the trade-offs that will feed into our integrated systems model, which will ultimately determine the best combination of target, laser, final optics, and reactor chamber design for an inertial fusion power plant.