Absolute cross-section measurements for electron impact ionisation of Li-like N4+, O5+and Ne7+ions

Defrance, Pierre; Chantrenne, S.; Rachafi, S.; Belić, D.; Jureta, Jozo; Gregory, D. C.; Brouillard, F.

doi:10.1088/0953-4075/23/14/020

Cited by 26 publications

(22 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6. The experiment of Defrance et al (1990) has few data points at energies below the peak in cross section, but this work does agree in that region. Above that, they lie higher than this work and their results are closer to Dere.…”

Section: O VImentioning

confidence: 61%

Effects of density on the oxygen ionization equilibrium in collisional plasmas

Dufresne

Zanna

Badnell

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Abstract The ion populations most frequently adopted for diagnostics in collisional plasmas are derived from the density independent, coronal approximation. In higher density, lower temperature conditions, ionisation rates are enhanced once metastable levels become populated, and recombination rates are suppressed if ions recombine into Rydberg levels. As a result, the formation temperatures of ions shift, altering the diagnostics of the plasma. To accurately model the effect of ionisation from metastable levels, new electron impact, ionisation cross sections have been calculated for oxygen, both for direct ionisation and excitation–auto-ionisation of the ground and metastable levels. The results have been incorporated into collisional radiative modelling to show how the ionisation equilibrium of oxygen changes once metastable levels become populated. Suppression of dielectronic recombination has been estimated and also included in the modelling, demonstrating the shifts with density in comparison to the coronal approximation. The final results for the ionisation equilibrium are used in differential emission measure modelling to predict line intensities for many lines emitted by O ii-O vi in the solar transition region. The predictions show improved agreement by 15-40% for O ii, O vi and the inter-combination lines of O iii-O v, when compared to results from coronal approximation modelling. While there are still discrepancies with observations of these lines, this could, to a large part, be explained by variability in the observations.

show abstract

Section: O VImentioning

confidence: 61%

Effects of density on the oxygen ionization equilibrium in collisional plasmas

Dufresne

Zanna

Badnell

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…For N v, the measurements of Crandall et al (1979) are ∼10% smaller than Defrance et al (1990) below 300 eV, but 10% larger above 1000 eV. In the intermediate range, where the EA onset occurs, the agreement is better than 5%.…”

Section: Di: 2s Cross-sectionsmentioning

confidence: 83%

X-ray emission from thin plasmas

Urdampilleta

Kaastra

Mehdipour

2017

A&A

View full text Add to dashboard Cite

Every observation of astrophysical objects involving a spectrum requires atomic data for the interpretation of line fluxes, line ratios, and ionization state of the emitting plasma. One of the processes that determines it is collisional ionization. In this study, an update of the direct ionization (DI) and excitation-autoionization (EA) processes is discussed for the H to Zn-like isoelectronic sequences. In recent years, new laboratory measurements and theoretical calculations of ionization cross-sections have become available. We provide an extension and update of previous published reviews in the literature. We include the most recent experimental measurements and fit the cross-sections of all individual shells of all ions from H to Zn. These data are described using an extension of Younger's and Mewe's formula, suitable for integration over a Maxwellian velocity distribution to derive the subshell ionization rate coefficients. These ionization rate coefficients are incorporated in the high-resolution plasma code and spectral fitting tool SPEX V3.0.

show abstract

“…Surprisingly, there have been few reports of absolute electron-impact ionization cross section measurements for multicharged neon ions. Experimental cross sections for only Ne" ¤ [2,3], Ne& ¤ [4], and Ne' ¤ [5] have been published. Ionization cross sections for neon are critical in modeling and diagnosing the ITER tokamak since neon is a prime candidate impurity for radiation power exhaustion in the divertor [6].…”

Section: Introductionmentioning

confidence: 99%

Absolute cross sections for electron-impact single ionization ofNeq+(q=2,4–6) ions

Bannister

1996

Phys. Rev. A

View full text Add to dashboard Cite

Absolute total cross sections for electron-impact single ionization of Ne qϩ (qϭ2,4-6͒ ions have been measured using a crossed-beams technique from below the ground-state ionization threshold to 800 eV with typical total uncertainties near the peak of the cross sections ranging from 9% for Ne 2ϩ to 13% for Ne 6ϩ . Details of the apparatus and experimental procedures used in this study are presented along with a discussion of the experimental uncertainties. The measured cross sections for all four ions are dominated by direct ionization and are in excellent agreement with the Lotz semiempirical formula. Ionization rate coefficients and fitting parameters calculated from the measured cross sections are also reported. ͓S1050-2947͑96͒03008-9͔PACS number͑s͒: 34.80.Kw

show abstract

Absolute cross-section measurements for electron impact ionisation of Li-like N⁴⁺, O⁵⁺and Ne⁷⁺ions

Cited by 26 publications

References 19 publications

Effects of density on the oxygen ionization equilibrium in collisional plasmas

Effects of density on the oxygen ionization equilibrium in collisional plasmas

X-ray emission from thin plasmas

Absolute cross sections for electron-impact single ionization ofNeq+(q=2,4–6) ions

Contact Info

Product

Resources

About