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Recently calculated electron impact excitation rates for transitions in helium-like Cl XVI are used to derive the electron temperature sensitive emission line ratio (G) and the electron density sensitive ratio (R). These calculations, which differ from others performed previously, are compared with experimental R and G ratios obtained from X-ray spectra from the JET plasma, for which the electron temperature and density have been measured by independent methods. The R ratio is approximately at its low density limit for this device and is therefore not electron density sensitive. However, it does function as an electron temperature diagnostic, as does the G ratio. A comparison is also made with the previously reported results from the Alcator-C tokamak, where the experimental results lie in the electron density sensitive region. The results show good agreement between theory and observation, with discrepancies of typically 7% in R and 10% in G for JET. A departure from coronal equilibrium due to diffusion effects is taken into account for the JET plasma conditions, and the resulting non-coronal ionisation balance is found to produce changes to the theoretical ratios in regions removed from the centre of the JET plasma.

Additional information

Authors: COFFEY I H ET AL., The Queen's University of Belfast, Department of Pure and Applied Physics, Northern Ireland (GB);BARNSLEY R, JET Joint Undertaking, Abingdon, Oxon. (GB);DICKSON W J, JET Joint Undertaking, Abingdon, Oxon. (GB);LAWSON K D, AEA Fusion, Culham Laboratory, Abingdon, Oxon. (GB);PEACOCK N J, AEA Fusion, Culham Laboratory, Abingdon, Oxon. (GB)
Bibliographic Reference: Report: JET-P(91)49 EN (1991) 14 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
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