Universal heavy element CXS modelling

(part of theme Charge Exchange Spectroscopy)

Objective

Charge exchange spectroscopy is in the process of extension to heavier species (argon and beyond) with issues of the role of CX for highly ionised ions of heavy elements such as tungsten. Upper emitting levels of visible CXS lines advance to higher n-shell at high z where collisional mixing establishes a bundle-n population model. State selective CX cross-section data for highly ionised ions must be based on extrapolated universal parametric forms established at low/moderate z. Several adjacent ions of a heavy element are simultaneous receivers at a localised point each emitting many transitions. The appropriate models are enabled here delivering the complete sets of CXS emissivity coefficients for use in analysis with heavy elements.

Specific tasks

• Implement the infinite n-shell bundle-n population model driven by charge exchange recombination from fast H(n=1) and H(n=2) beams using universal parametric forms for state selective cross-sections .
• Implement merging of bundle-n population model projection matrices onto the l-redistributive cascade model for n-shells below the mixing limit.
• Enable production of complete CXS adf12 emissivity sets for heavy element ion groups and assembly of feature emissivities of format adf40.
• Revision. Timing is subject to laboratory responses and indeterminate at this stage.