Shock ignition of the Focused Energy IFE target designs

Focused Energy is pursuing inertial fusion energy with advanced ignition schemes – proton fast ignition and shock ignition – using laser direct drive to implode a large fuel mass (~ 2.5 mg DT) with a moderate implosion velocity (200 to 300 km/s). Two reference high gain targets for proton fast ignition were designed that tradeoff laser intensity and in-flight-aspect-ratio, which are metrics for laser plasma interaction and hydrodynamic instability risks. Each implosion can be driven by either 530 nm (2ω) or 350 nm (3ω) wavelength laser light. Here, we study shock ignition and augmented shock ignition of the same targets. We consider both 2ω and 3ω drive and discuss the tradeoff between compression pulse power (and hence implosion velocity) and shock ignition spike power, and their consequences on 1D ignition threshold factors.