A project based on Multi-Configuration Dirac-Fock calculations for plasma spectroscopy

TL;DR

This paper introduces a MCDF-based plasma spectroscopy project, detailing the code, methods for handling complex transition arrays, and demonstrating its application in modeling and analyzing hot plasma spectra and atomic data.

Contribution

It presents an improved Partially-Resolved-Transition-Array method and a comprehensive MCDF code for plasma spectroscopy, including spectral modeling and atomic data calculations.

Findings

Better agreement with detailed line calculations.

Successful comparison with experimental spectra.

Versatile atomic data computations for non-LTE plasmas.

Abstract

We present a project dedicated to hot plasma spectroscopy based on a Multi-Configuration Dirac-Fock (MCDF) code, initially developed by J. Bruneau. The code is briefly described and the use of the transition-state method for plasma spectroscopy is detailed. Then an opacity code for local-thermodynamic-equilibrium plasmas using MCDF data, named OPAMCDF, is presented. Transition arrays for which the number of lines is too large to be handled in a Detailed-Line-Accounting calculation can be modeled within the Partially-Resolved-Transition-Array method or using the Unresolved-Transition-Arrays formalism in jj-coupling. An improvement of the original Partially-Resolved-Transition-Array method is presented which gives a better agreement with Detailed-Line-Accounting computations. Comparisons with some absorption and emission experimental spectra are shown. Finally, the capability of the MCDF code to compute atomic data required for collisional-radiative modeling of plasma at non local thermodynamic equilibrium is illustrated. Additionally to photoexcitation, this code can be used to calculate photoionization, electron impact excitation and ionization cross-sections as well as autoionization rates in the Distorted-Wave or Close Coupling approximations. Comparisons with cross-sections and rates available in the literature are discussed.