Hydrodynamics of inertial confinement fusion: conventional hot spot and shock ignition

Thesis (Ph. D.)--University of Rochester. Department of Physics and Astronomy, 2015.The hydrodynamics of inertial confinement fusion (ICF) implosions, both conventional hot spot and shock ignition (SI), are discussed. A one-dimensional planar compressible–piston-like model is used to investigate the basic physics behind conventional hot spot and shock-ignition implosions. Three ignitor shock techniques are found to mitigate the effects of rarefaction waves, enhance the stagnation hot-spot pressure, and improve the ignition conditions. These techniques are compared and the optimal energy ratio between the initial shell kinetic energy and the ignitor pulse energy is determined. We demonstrated for the first time the ability to launch shocks of several-hundred Mbars in spherical targets at SI relevant laser intensities, a milestone for SI. The temporal delay between the launching of the strong shock at the outer surface of the spherical target and the shock converges at the center is used to infer the ablation and shock pressures. Peak ablation pressures exceeding 300 Mbar are inferred at absorbed laser intensities of ~3 x 1015 W/cm2. The theory of ignition for ICF capsules is used to determine hydrodynamically-equivalent ignition performance requirements on OMEGA. A reasonable combination of neutron yield and areal density for OMEGA hydro-equivalent ignition is ~6 x 1013 and 0.3 g/cm2, respectively