Answers are grounded in this paper and cite their sources.
We report new measurements of He⁺⁺/He⁺ ratios in three energy ranges. Near threshold, where only photoionization contributes, we find a ratio systematically lower than previously published measurements. From 2 to 6 keV, where Compton ionization gradually supplants photoionization as the dominant ionization mechanism, theory and experiment are in substantial agreement. Far above threshold where Compton ionization dominates, theories diverge markedly. Comparison with present results indicates asymptotic values have been established for photoionization but not Compton ionization.
No takes yet. Share an insight, caveat, or question.
Levin et al. (1996) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: