CER SEMINAR

Quantum Hydrodynamics: Theory and Computation with Application to Charged Particle Stopping in Warm Dense Matter

David Michta, Lawrence Livermore National Laboratory
September 12, 2017, 11:00am - 12:00pm, Room 232 SERF Building

ABSTRACT:

The study of charged particle (CP) stopping in warm dense matter (WDM) conditions is vital to understanding laser-plasma interaction experiments and fast alpha energy deposition in inertial confinement fusion (ICF). The purpose of my thesis is to develop a fully dynamical and quantum mechanical simulation capability in WDM motivated specifically by the problem of CP stopping. This work consists of three major components: theoretical development; computational and algorithmic development; and code verification and validation. This problem is approached using Quantum Hydrodynamic (QHD) theory, with forces on a dynamic electron fluid derived from Density Functional Theory (DFT). First, the single-particle Madelung QHD model is rigorously extended to many-particle systems and, under certain constraints, is shown to reproduce Thomas-Fermi-Dirac theory. Next, the phenomenological Bloch QHD model is studied using a finite temperature density-gradient-corrected Thomas-Fermi equation of state (EOS), and linearized theory is derived for ion acoustic and Langmuir dispersion relations and dynamic screening. A parallelized code is developed in C that simulates a QHD electron fluid coupled to discrete Molecular Dynamic (MD) ions. This simulation capability is verified with predictions from linearized theory and validated with experimental charged particle stopping data, with simulations conducted for plasma conditions spanning cool dense matter to hot dense matter. Appropriate pseudo-potentials are determined for the given physical conditions and projectile momenta in order to improve computational efficiency.