Multidimensional hydrodynamic simulations for the design of shock-ignited inertial fusion targets

Shock ignition is a recently proposed approach to inertial confinement thermonuclear fusion (ICF). A hollow spherical target, containing a frozen layer of deuterium-tritium, is first imploded by a time shaped, multi-beam laser pulse (providing nearly spherically symmetrical irradiation). At a time close to implosion stagnation an additional laser pulse drives a strong converging shock wave, causing the formation of a hot spot at the centre of the compressed fuel and then thermonuclear ignition. The design of inertial fusion targets is based on analytical models and on massive numerical simulations using radiation-hydro-nuclear codes. In the first part of the talk I will briefly review physical models employed by fluid codes for ICF, highlighting intrinsic multi-scale features (in both space and time). I will then describe the main features of the DUED code, developed by my group, and the rationale behind its design. In particular, I will illustrate recent improvements necessary for accurate, high resolution studies of shock-ignited targets. In the second part of the talk I will discuss recent shock ignition studies, including a first target design, analysis of sensitivity to hydrodynamic instabilities, to non-uniform irradiation, and to laser mispointing/target mispositioning. I will also present gain curves (ratio of fusion energy to laser energy vs laser energy) for targets scaled accordingly to a recently developed analytical model. Finally, I will outline plans for the demonstration of shock ignition and discuss the required improvements in simulation capabilities. Work supported by the Italian MIUR project PRIN2009FCC9MS.