Emery, Mark H.

A Survey of Three Scalable Hydrodynamics Codes ( Book )
1 edition published in 1996 in English and held by 1 library worldwide
Massively parallel computer architectures offer greater memory capacity and faster computational speeds through the cooperative effort of hundreds or thousands of individual processors. This makes possible the solution of problems previously impractical with conventional vector supercomputers. This report presents a survey and partial assessment of several different hydrodynamic codes with a focus on scalability; i.e., codes that are amenable to implementation on high-performance parallel computer architectures. Issues, such as decomposing the physical problem into naturally parallel parts, load balancing the computation across multiple processors, effectively communicating data between processors, and manipulation and display of large sets of data are discussed from the perspective of three different hydrodynamic codes.

A Scalable Software Plan for the Undersea Warheads' Modeling and Simulation Program ( Book )
1 edition published in 1996 in English and held by 1 library worldwide
The Department of Defense has embarked on an underwater explosion project to couple underwater explosion hydrodynamics with new capabilities in large deformation structural mechanics. In a related effort, DoD has recognized the urgent need of a self-consistent numerical capability for modeling explosion and shock effects in surf zone seafloor sediments with seawater and free air pore fluid, to accelerate the progress of performance prediction of mine countermeasure efforts and for modeling the response of geometrically complex structures buried in sand or soil under blast and shock loads. This report summarizes a research plan which involves the development and implementation of a scalable, fully coupled fluid structure interaction model for simulating the response of geometrically complex structures subjected to unsteady blast and bubble loads stemming from explosions in deep ocean and the surf zone. This multilevel, multiyear plan will couple a scalable, finite difference hydrodynamics code for modeling the generation and evolution of propagating explosive blast waves in a medium (water, partially or fully saturated sand, 'dry' soils, and sands) to a scalable, finite-element structural mechanics code for modeling the response of complex, multidimensional structures to the loads and stresses stemming from the medium.

Constitutive Modeling of Air and Water Saturated Sand for Shock Propagation Modeling. Workshop Summary and Recommendations ( Book )
1 edition published in 1995 in English and held by 1 library worldwide
The mine countermeasure research program is an Office of Naval Research program that addresses the physical characterization and modeling of the surf zone environment, explosive shock propagation and mitigation in this environment, and the means to improve the performance prediction of mine countermeasure efforts in the surf zone. This report summarizes the results of the Workshop on Constitutive Modeling of Air and Water Saturated Sand for Shock Propagation Modeling sponsored by the Naval Research Laboratory. The objectives of this workshop were to appraise the present state of knowledge with respect to the characterization of the air and water saturated sandy medium, the experimental evidence for shock mitigation and propagation in this medium, the present constitutive modeling capabilities, and to develop a focused research effort to address the complex physics issues related to this task. Participants discussed issues associated with mine countermeasure systems including shock wave propagation in sandy sediments with water and free-air pore fluid, measurement of the mechanical properties of both dry and partially saturated sand, hydrodynamic modeling of this environment, and continuum and micromechanical aspects of constitutive models. (MM).

Shock-Free Acceleration of Laser Driven Targets ( Book )
1 edition published in 1992 in English and held by 1 library worldwide
The ability of recently developed laser smoothing techniques to produce uniform ablation pressures is strongly contingent on the degree of thermal smoothing. Thermal smoothing is not effective at reducing residual laser nonuniformities during the start up phase of a shaped, reactor-like laser pulse. The impact of the first shock can be diminished by adiabatically compressing the target with a temporally long, slowly rising laser pulse. This Memorandum Report discusses an elastic-plastic laser-matter-interaction model and shows that a shock-free, induced spatial incoherence-smoothed laser pulse can accelerate a target to nearly the conditions required for uniform implosion.

The Rayleigh-Taylor Instability in Ablatively Accelerated Targets with 1, 1/2 and 1/4 Micrometers Laser Light ( Book )
1 edition published in 1987 in English and held by 1 library worldwide
The results of a series of detailed numerical simulations are presented for the Rayleigh-Taylor instability in laser ablatively accelerated targets for a fairly wide range of initial conditions. It is shown that the Rayleigh-Taylor growth rate in an ablative environment is a strong function of the laser wavelength. For perturbation wavelengths about 3 times the inflight target thickness, the ratios of the numerical growth rates to the classical growth rates are of the order of 1/1.5, 1/2.5 and 1/3.5 for 1, 1/2 and 1/4 micrometer laser light respectively. The numerical results are in good agreement with out theoretical based on the ablative convection of vorticity away from the unstable ablation front. These results provide strong evidence for the viability of high aspect ratio shells in direct drive laser fusion. Keywords: Laser ablation; Inertial confinement fusion; Hydrodynamic instabilities.

Hydrodynamic Aspects of the Split-Foil Laser Target Design ( Book )
1 edition published in 1986 in English and held by 1 library worldwide
Hydrodynamic simulations of exploding copper foils, which are irradiated on one side by 1.06 micron laser light, indicated that peak axial electron number density is more easily controlled with split-foil target design. Results from a series of simulations with solid copper foils that range in width from 500A to 1500A show that while peak electron temperature and time of burnthrough can be varied, evolved electron number densities are approximately bounded from above by 3 X 10 to the 20th power particles/cc. By increasing foil thickness to 1 micron and introducing aa slit on the foil axis of 100 micron width, uniform plasmas with electron number densities on the order of 6 X 10 to the 20th power particles/cc can be generated. Essentially the same results are obtained from simulations with split selenium foils. Keywords: X-ray lasers, Laser-matter interactions, Hydrodynamic simulation.

Two-dimensional simulation of lower hybrid resonance heating by Mark H Emery ( Book )
1 edition published in 1974 in English and held by 1 library worldwide

Electric field correlations in the guiding-center plasma by Glenn Joyce ( Book )
1 edition published in 1973 in English and held by 1 library worldwide

A comparison of various numerical solutions to the nonlinear Vlasov equation by Mark H Emery ( Book )
1 edition published in 1972 in English and held by 1 library worldwide

Numerical simulation of lower hybrid resonance heating by Mark H Emery ( Book )
1 edition published in 1974 in English and held by 1 library worldwide