Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Recombination rate coefficients of Be-like neon
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
2008 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 489, no 2, 829-835 p.Article in journal (Refereed) Published
Abstract [en]

Aims. Merged-beam and plasma recombination rate coefficients for Be-likeNe vii were extracted from results of a merged-beam typeexperiment.Methods. The cryring heavy-ion storage ring was used to determine merged-beam recombination rate coefficients for Be-likeNe6+.Recombined Ne5+ ions were separated from the stored beam in the first dipole magnet following the electron-ion interaction region.Field-ionization at this dipole magnet prevented detection of recombination into states with the principal quantum number n > ncutoff =23. To account for the field-ionization effects, results obtained with autostructure calculations were used for recombinationchannels above ncutoff. The merged-beam recombination rate coefficients were then convoluted with Maxwellian electron energydistributions in the 103−3 × 106 K temperature region, to obtain plasma recombination rate coefficients.Results. Good agreement was found between the experimentally derived rate coefficient spectrum and results of the autostructurecalculation. At low energies, several strong dielectronic recombination resonances belonging to the spin-forbidden 2s2p(3PJ)nl seriesdominate the merged-beam spectrum. Recombination through these states dominates at low-temperatures, e.g. at 103 K recombinationthrough these resonances is more than one order of magnitude higher than the radiative recombination rate coefficient. Most data fromthe literature significantly underestimate the low-temperature plasma rate coefficients below 104 K, with only two calculations showingrate coefficients comparable to our results.Strong contributions from trielectronic recombination were found in the merged-beam spectrum of Be-like Ne, associated with doubleexcitation of the Be-likeNe core, during the attachment of the free electron. Calculated trielectronic recombination resonance positionsagree with experimental peaks, however compared to the experiment, the calculation underestimates the strength of trielectronicrecombination.

Place, publisher, year, edition, pages
2008. Vol. 489, no 2, 829-835 p.
Keyword [en]
atomic data, atomic processes, line: formation, plasmas, Sun: general
National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:su:diva-33244DOI: 10.1051/0004-6361:200810295ISI: 000259601500046OAI: oai:DiVA.org:su-33244DiVA: diva2:282761
Available from: 2009-12-21 Created: 2009-12-21 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Electron - Ion Recombination Studies of Astrophysically Relevant Ions: Storage Ring and Electron Beam Ion Trap Based Measurements
Open this publication in new window or tab >>Electron - Ion Recombination Studies of Astrophysically Relevant Ions: Storage Ring and Electron Beam Ion Trap Based Measurements
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis contains experimental work that was performed at two state-of-the art devices for electron-ion collision physics, at a heavy-ion storage ring and at an Electron Beam Ion Trap. As a result, absolute recombination rate coefficients for H-like Si, He-like Si, Be-like Si, and Na-like Si, as well as Be-like Ne, Na-like S and Na-like Ar are reported over a wide energy range from μeV to keV. The experimentally derived recombination spectra are compared with results of Many Body Perturbation Theory calculations and AUTOSTRUCTURE calculations. Furthermore, the effect of external electric fields on the recombination rate is investigated for two Na-like ions, and a strong enhancement of dielectronic recombination into high Rydberg states is observed. Experimental plasma rate coefficients are derived for the studied ions for the first time and are compared with calculated values available in the literature. In the EBIT experiment, a novel extraction method provides complete charge state spectra of the ions for every extraction. Absolute DR rate coefficients for both H-like Si and He-like Si are obtained from the same measurement. Comparison with recorded X-ray spectra enables the separation of the photon spectra arising from charge-changing and charge-preserving reactions and facilitates the extraction of electron impact excitation rate coefficients.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2009. 150 p.
Keyword
atomic processes, electron-ion recombination, plasma
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-33254 (URN)978-91-7155-989-0 (ISBN)
Public defence
2010-01-29, sal FB42, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 14:30 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 6: Submitted. Paper 7: Submitted. Available from: 2010-01-07 Created: 2009-12-21 Last updated: 2010-01-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Orban, IstvanSchuch, Reinhold
By organisation
Department of Physics
In the same journal
Astronomy and Astrophysics
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 30 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf