"Scaling Laws for Diffusion in Crystallized Plasma from Molecular Dynam" by Dany Yaacoub

Graduation Term

Spring 2025

Degree Name

Master of Science (MS)

Committee Chair

Matt Caplan

Committee Co-Chair

Neil Christensen

Committee Member

Mahua Biswas

Abstract

Diffusion coefficients for crystallized Coulomb plasmas are essential microphysics input for modeling white dwarf cores and neutron star crusts. Solving for diffusion coefficients require running large molecular dynamics simulations with thousands of particles over millions of timesteps. The diffusion in a crystallized plasma has been largely ignored and is often taken to be zero in stellar evolution codes. We find that not only is this incorrect, but we find that the diffusion in a crystallized plasma can be modeled completely using a universal scaling law independent of screening. Our simulations also show that the dominant mode of diffusion in a Coulomb crystal is through the formation of vacancy-interstitial pair defects in the lattice due to thermal fluctuations.

Access Type

Thesis-Open Access

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