Average-atom Ziman resistivity calculations in expanded metallic plasmas: effect of mean ionization definition

TL;DR

This paper investigates electrical resistivity in expanded metallic plasmas using the average-atom Ziman model, emphasizing the importance of a consistent mean ionization definition for accurate results.

Contribution

It introduces a generalized mean ionization definition for expanded plasmas that improves agreement with experimental data and clarifies the impact of ionization choices.

Findings

Proposed a new mean ionization definition for expanded plasmas.

Achieved better agreement with experimental resistivity data.

Highlighted the importance of consistency in ionization models.

Abstract

We present calculations of electrical resistivity for expanded boron, aluminum, titanium and copper plasmas using the Ziman formulation in the framework of the average-atom model. Our results are compared to experimental data, as well as with other theoretical calculations, relying on the Ziman and Kubo-Greenwood formulations, and based on average-atom models or quantum-molecular-dynamics simulations. The impact of the definition of ionization, paying a particular attention to the consistency between the latter and the perfect free electron gas assumption made in the formalism, is discussed. We propose a definition of the mean ionization generalizing to expanded plasmas the idea initially put forward for dense plasmas, consisting in dropping the contribution of quasi-bound states from the ionization due to continuum ones. It is shown that our recommendation for the calculation of the quasi-bound density of states provides the best agreement with measurements.