Screening corrections to the Coulomb crystal elastic moduli

TL;DR

This paper calculates how electron screening affects the elastic properties of neutron star crusts modeled as Coulomb crystals, providing formulas for improved neutron star oscillation models.

Contribution

It introduces a method to incorporate electron screening corrections into the elastic moduli of neutron star crusts using a Thomas-Fermi model.

Findings

Electron screening significantly modifies the shear modulus.

Analytic formulas for screening corrections are provided.

Results aid in precise neutron star oscillation modeling.

Abstract

Corrections to elastic moduli, including the effective shear modulus, of a solid neutron star crust due to electron screening are calculated. At any given mass density, the crust is modelled as a body-centred cubic Coulomb crystal of fully ionized atomic nuclei of a single type with a polarizable charge-compensating electron background. Motion of the nuclei is neglected. The electron polarization is described by a simple Thomas-Fermi model of exponential electron screening. The results of numerical calculations are fitted by convenient analytic formulae. They should be used for precise neutron star oscillation modelling, a rapidly developing branch of stellar seismology.