The hybrid opacity code SCO-RCG: recent developments

TL;DR

The paper introduces recent enhancements to the SCO-RCG hybrid opacity code, which combines statistical and detailed atomic calculations to accurately model spectra of multicharged-ion plasmas, validated against experimental data.

Contribution

It extends the PRTA model within the hybrid approach and improves criteria for switching between statistical and detailed spectral treatments.

Findings

Enhanced accuracy in spectral modeling of multicharged-ion plasmas.

Successful comparison of simulated spectra with experimental results.

Improved criteria for line treatment decision-making.

Abstract

Absorption and emission spectra of multicharged-ion plasmas contain a huge number of electron configurations and electric-dipolar lines, which can be handled by global methods. However, some transition arrays consist only of a small bunch of lines. For that reason, we developed the hybrid opacity code SCO-RCG combining the (statistical) super-transition-array method and the (detailed) fine-structure calculation (requiring the diagonalization of the Hamiltonian matrix) of atomic structure. In order to decide whether a detailed treatment of lines is necessary and to determine the validity of statistical methods, the code involves criteria taking into account coalescence of lines and porosity (localized absence of lines) in transition arrays. Data required for the calculation of detailed transition arrays (Slater, spin-orbit and dipolar integrals) are provided by the super-configuration code SCO, which takes into account plasma screening effects on wavefunctions. Then, level energies and lines are calculated by Cowan's code. Transition arrays for which a detailed treatment is not required or impossible are described statistically, by UTA (Unresolved Transition Arrays) and STA (Super Transition Arrays) formalisms used in SCO. Recent developments are presented, such as the extension of the PRTA (Partially Resolved Transition Array) model to the hybrid approach, as well as comparisons with experimental spectra (laser or Z-pinch).