High Density and High ρR Fuel Assembly for Fast Ignition Inertial Confinement Fusion

A method to assemble thermonuclear fuel at high densities, high ρR and low temperature is presented. Massive cryogenic shells can be imploded with a low implosion velocity on a low adiabat using the relaxation laser-pulse technique. While the low implosion velocity yields a low temperature hot spot, the low adiabat of the fuel leads to large peak values of the density and areal density. the low velocity and the shaped adiabat have also mitigating effects on the growth of hydrodynamic instabilities that should not significantly impact the fuel assembly of such massive shells. One dimensional simulations show that a 25kJ driver can assemble a 0.07 mg, 860 μm in diameter, cryogenic wetted-foam shell with a low implosion velocity of about 2.5.10''7 cm/s reaching peak ρR of 0.76-0.9 g/cm''2, peak densities of 700-95g/cc and relatively low central temperatures of about 3keV. The hot spot volume at time of peak ρR is only 20% of the high density volume above 300g/cc. This cold and dense fuel assembly is optimal for Fast Ignition inertial confinement fusion. This work was supported by the U. S. Department of Energy Office of Fusion Energy Sciences Cooperative Agreement No. DE-FEC02-04ER54789. (Author)