The Ar(17+) Ly(alpha 2)/Ly(alpha 1) ratio in Alcator C-Mod tokamak plasmas
2011 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 44, no 16, 165702- p.Article in journal (Refereed) Published
High-quality spectra of hydrogen-like Ar(17+) have been obtained from Alcator C-Mod tokamak plasmas using a spatially imaging high-resolution x-ray spectrometer system in an extensive study of the underlying high-n satellite lines. The ratio of Ly(alpha 2) (1S(1/2)-2P(1/2)) to Ly(alpha 1) (1S(1/2)-2P(3/2)) was found to be similar to 0.52 regardless of plasma parameters, which is somewhat greater than the ratio of the statistical weights of the upper n = 2 levels, 0.5. This difference is mainly due to the effects of collisional excitation of fine-structure sub-levels. For the observations presented here, electron densities were in an extended range from 3 x 10(19) to 4 x 10(20) m(-3) with electron and ion temperatures between 1 and 4 keV. Experimental results are compared to calculations from COLRAD, a collisional-radiative modelling code, and good agreement is shown.
Place, publisher, year, edition, pages
2011. Vol. 44, no 16, 165702- p.
hydrogen-like ions, ti-xxii, precision-measurement, intensity ratios, fine-structure, atomic levels, one-electron, lamb shift, temperature, transitions
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:kth:diva-41801DOI: 10.1088/0953-4075/44/16/165702ISI: 000294890800035ScopusID: 2-s2.0-80051697796OAI: oai:DiVA.org:kth-41801DiVA: diva2:445135
QC 201110032011-10-032011-10-032011-10-03Bibliographically approved