Studies on shock ignition targets for inertial fusion energy

Shock ignition [1] is an approach to direct-drive inertial confinement fusion (ICF) in which the stages of compression and hot spot formation are partly separated. The fuel is first imploded at lower velocity than in conventional ICF. Close to stagnation an additional intense laser spike drives a strong converging shock, which contributes to hot spot formation. Shock ignition shows potentials for high gain at UV laser energy below 1 MJ, and could be tested on the National Ignition Facility [2] or Laser Megajoule. Due to the lower implosion velocity, issues related to hydrodynamic instabilities are relaxed. On the other hand, the interaction of the laser spike with the plasma occurs in a regime where parametric instabilities are expected to become relevant.