A Research Program for Ion-Based Fast Ignition

We present a research program to evaluate fast ignition (FI) lit by laser-driven ion beams heavier than protons. Compared to protons, heavier ions have the potential advantage of a more localized energy deposition, which might translate into a significantly lower total beam-energy requirement. The starting points for this research are the target-design requirements in the study by Temporal {\it et al.} [Phys. Plasmas 9 (2002) 3098] and the recent demonstration of the capability to produce laser-driven quasi-mono-energetic ion beams, at the Los Alamos Trident laser facility by Hegelich {\it et al.} [Nature, submitted (2005)]. Based on our present theoretical understanding of the plasma physics and of the target-surface physics involved, we outline the development of the capability to accelerate mono-energetic beams within the constraints of a fast-ignition target. We discuss experiments necessary to validate, in the FI regime, applicable theory and modeling in warm-dense matter and beam-dense plasma interactions. Ultimately, we apply those improved models and existing target-design capability to understand the tradeoffs associated with using different ion species in FI, to optimize the scheme, and to design FI proof-of-principle experiments in a facility such as Z-R and Z-Beamlet