Ionization by electron impacts and ionization potential depression

Abstract We calculate the cross-section of ionization by free-electron impacts in high or moderate density plasmas. show that so-called potential depression (IPD) strongly affects magnitude high-density domain. use well-known IPD formulas Stewart–Pyatt and Ecker–Kröll. A more recent approach based on classical molecular dynamics simulation is also investigated. The latter provides an alternative way to values. At near-solid densities effects degeneracy should be rates are then calculated within Fermi–Dirac statistics. first semi-empirical formula Lotz for cross-section. results may differ significantly from measured cross-sections calculations with reliable atomic codes. Then, a second step, we propose new combines polynomial expansion terms ratio energy incident electron energy. coefficients adjusted fit provided robust great advantage it allows fully analytical calculation rate. Our compared experiments measuring IPDs, rate aluminum at Be-like CNO ions.