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Abstract

SPATIO-TEMPORAL EVOLUTION OF WARM DENSE PLASMAS: MOLECULAR

DYNAMICS MODELING Cole Wenzel and Gennady Miloshevsky

Virginia Commonwealth University, Department of Mechanical and Nuclear Engineering, 401

West Main St, Richmond, VA 23284-3015

The exo-atmospheric detonation of nuclear device would be of great impact on the material integrity of orbiting satellites. The spectral energy distribution of high intensity X-ray flux, ~10 28 -10 35 photons/(cm 2 ∙s), originating from a nuclear blast is described by the Planck's blackbody function with the temperature from 0.1 keV to 10 keV. Particular damage would occur to the multi-layered, solar cell panels of satellites. However, the X-ray flux incident upon the solar panels is inversely proportional to the square of the distance from a point where a weapon was detonated. For example, the X-ray flux is reduced by a factor of 10 -10 at the distance of 100 km. Even accounting for this geometric factor, the enormous power density, ~0.1 - 10 4 GW/cm 3 , absorbed within a few microns of a Ge slab of solar cells produces the extreme pressures and temperatures. The X-ray induced blow-off and Warm Dense Plasma (WDP) formation on the surface of materials, particularly in a gap between the unshielded Ge elements is initiated. In this work, the profiles of deposited energy and power density produced by cold X- rays (~ 1 keV) in the multi-layered materials are calculated using the Monte Carlo method within the Geant4 software toolkit. The power density is used as an input for the Molecular Dynamics (MD) modeling of WDP formation and expansion into vacuum. The MD computational model is implemented within the LAMMPS software toolkit. The spatio-temporal evolution of WDP as well as its temperature, stress, and mass density distribution are investigated for different X-ray irradiation conditions. Presenting author: Cole Wenzel This work is supported by Defense Threat Reduction Agency, Grant No. DTRA1‐19‐1‐0019.

Publication Date

2020

Disciplines

Mechanical Engineering | Nuclear Engineering

Is Part Of

VCU Graduate Research Posters

SPATIO-TEMPORAL EVOLUTION OF WARM DENSE PLASMAS: MOLECULAR DYNAMICS MODELING

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