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Inertial confinement fusion and x-ray laser advances

E. Michael Campbell

Significant advances in both inertial confinement fusion and laboratory x-ray lasers have been made at the Nova laser at Lawrence Livermore National Laboratory in 1987. For inertial confinement fusion to succeed in producing net energy gain in the laboratory, it is necessary to implode capsules containing deuterium-tritium (DT) fuel to densities approaching 200 g/cm3 and ion temperatures of approximately 4 keV (4.4 X 10^7 °K). This represents a fuel pressure of ~ 2.7 X 10^11 atmospheres. To achieve such conditions with reasonable ablation pressures (PABL ~ 10^8 atmospheres) and with liquid DT fuel, the fuel radius must be reduced 20 to 40 fold. The ratio of the initial fuel radius to final fuel radius is commonly referred to as the convergence ratio. To achieve such high convergence implosions, stringent requirements are placed on the uniformity of the ablation pressure (pressure uniformity on the capsule surface must be better than 2-3%) and hydrodynamic instabilities.