Multi-scale simulation of laser acceleration of ions for fast ignition ICF

Brian Albright
Los Alamos National Laboratory

In interactions of ultra-intense short-pulse lasers with thin solid targets, a halo of energetic electrons is created which can accelerate MeV/nucleon ion beams to currents of several MA. These beams have several features which make them ideal candidates for fast ignition, including: short pulse length (< 1 ps), high beam current (> 1 MA), low transverse emittance, and high accelerating field (several TV/m--six orders of magnitude higher than in conventional accelerators). The physics of ionization, ion acceleration and transport in these experiments and in fast ignition ICF targets occurs over a wide range of length and time scales, which makes end-to-end simulation of such systems a challenge. Consequently, in the LANL theory effort, several numerical simulation techniques at varying levels of fidelity are currently being applied to this problem, including rad-hydro modeling (LASNEX), implicit modeling (ANTHEM), hybrid modeling (BILBO), and PIC modeling (TRISTAN and
VPIC-3) of surrogate target plasmas. In this presentation, two reduced numerical models which the author has been involved in, the hybrid and implicit models, will be described together with discussion of the underlying
the physics motivation for the approaches taken, the physics retained, and the trade-offs made in order for the simulations to be practical on current computing architectures. Verification and validation will also be discussed.

*Collaborators: E. S. Dodd, J. M. Kindel, R. J. Mason, M. J. Schmitt,
B. M. Hegelich, J. C. Fernandez

This work was performed under the auspices of the University of California Los Alamos National Laboratory under contract W-7405-ENG-36 and was supported by project 20040064DR of the LANL Laboratory Directed Research and Development Program (LDRD).

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