---
abstract: 'We describe the influence of electron-impact multiple ionization (EIMI) on the ionization balance of collisionally ionized plasmas. We are unaware of any previous ionization balance calculations that have included EIMI, which is usually assumed to be unimportant. Here, we incorporate EIMI cross-section data into calculations of both equilibrium and non-equilibrium charge-state distributions (CSDs). For equilibrium CSDs, we find that EIMI has only a small effect and can usually be ignored. However, for non-equilibrium plasmas the influence of EIMI can be important. In particular, we find that for plasmas in which the temperature oscillates there are significant differences in the CSD when including versus neglecting EIMI. These results have implications for modeling and spectroscopy of impulsively heated plasmas, such as nanoflare heating of the solar corona.'
author:
- 'M. Hahn and D. W. Savin'
bibliography:
- 'MEII.bib'
title: 'Influence of Electron-Impact Multiple Ionization on Equilibrium and Dynamic Charge State Distributions: A Case Study Using Iron'
---

Introduction {#sec:intro}
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Collisionally ionized plasmas are formed in numerous astrophysical sources, such as the Sun and other stars, supernova remnants, galaxies, and the intracluster medium of galaxy clusters. Interpreting observations and modeling astrophysical processes in these objects requires knowledge of the underlying 