Deposition and drive symmetry for light ion ICF targets

Light ion beam ICF is a concept in which intense beams of low atomic number ions would be used to drive ICF targets to ignition and gain. Three dimensional analytic approximations indicate that at least twelve beams would be required to drive an indirect drive target with adequate symmetry. Here, results from two dimensional numerical simulations are presented describing the ion deposition and drive symmetry aspects of such a target for which the ion beams are approximated as ring sources. For adequate symmetry in the two dimensional calculations, the simulations required six ring sources and two pole sources during the low power 'foot' pulse and four ring sources during the main ion beam drive pulse. If each ring represents five individual beams, this corresponds to 32 beams in the foot pulse and 20 beams in the main pulse. The corresponding two dimensional integrated LASNEX calculation, simulating the target from ion beam input to ignition and burn in the same code run, produced 591 MJ of thermonuclear yield with lithium ion beam sources containing a total input energy of 16 MJ.