The growth rate of the ablative Rayleigh-Taylor instability is approximated by gamma = square root[kg/(1 + kL)] - beta km/rho(a), where k is the perturbation wave number, g the gravity, L the density scale length, m the mass ablation rate, and rho(a) the peak target density. The coefficient beta was evaluated for the first time by measuring all quantities of this formula except for L, which was taken from the simulation. Although the experimental value of beta = 1.2+/-0.7 at short perturbation wavelengths is in reasonably good agreement with the theoretical prediction of beta = 1.7, it is found to be larger than the prediction at long wavelengths.
We performed integrated experiments on impact ignition, in which a portion of a deuterated polystyrene (CD) shell was accelerated to about 600 km/s and was collided with precompressed CD fuel. The kinetic energy of the impactor was efficiently converted into thermal energy generating a temperature of about 1.6 keV. We achieved a two-order-of-magnitude increase in the neutron yield by optimizing the timing of the impact collision, demonstrating the high potential of impact ignition for fusion energy production.
A computationally efficacious free-energy functional for studies of inhomogeneous liquid water J. Chem. Phys. 137, 044107 (2012) Fourth virial coefficients of asymmetric nonadditive hard-disk mixtures J. Chem. Phys. 136, 184505 (2012) Equation of state and jamming density for equivalent bi-and polydisperse, smooth, hard sphere systems J. Chem. Phys. 136, 124508 (2012) On the theoretical determination of the Prigogine-Defay ratio in glass transition J. Chem. Phys. 136, 124502 (2012) Communication: Thermodynamics of condensed matter with strong pressure-energy correlations Hugoniot data of diamond was obtained using laser-driven shock waves in the terapascal range of 0.5-2 TPa. Strong shock waves were generated by direct irradiation of a 2.5 ns laser pulse on an Al driver plate. The shock wave velocities in diamond and Al were determined from optical measurements. Particle velocities and pressures were obtained using an impedance matching method and known Al Hugoniot. The obtained Hugoniot data of diamond does not show a marked difference from the extrapolations of the Pavlovskii Hugoniot data in the TPa range within experimental errors.
Equation-of-state data, not only pressure and density but also temperature, for polystyrene (CH) are obtained up to 510 GPa. The region investigated in this work corresponds to an intermediate region, bridging a large gap between available gas-gun data below 60 GPa and laser shock data above 500 GPa. The Hugoniot parameters and shock temperature were simultaneously determined by using optical velocimeters and pyrometers as the diagnostic tools and the α-quartz as a new standard material. The CH Hugoniot obtained tends to become stiffer than a semiempirical chemical theoretical model predictions at ultrahigh pressures but is consistent with other models and available experimental data.
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