Dielectronic Recombination for Aluminum-Like Ions and Photoabsorption Cross Sections for Magnesium Ions at the K-Edge
Date of Award
Doctor of Philosophy
Dr. Thomas W. Gorczyca
Accurate and reliable recombination data are needed for modeling the ions in the finitedensity plasmas that may take place in solar flares and in divertors of magnetically confined fusion devices such as the International Thermonuclear Experimental Reactor (ITER). Dielectronic recombination (DR) is the dominant recombination mechanism in photoionized and collisionally-ionized plasmas. DR rate coefficients for M-shell argon ions have been calculated using a configuration-average approach. DR rate coefficients for the aluminumlike isoelectronic sequence are instead calculated using the state-of-the-art multiconfiguration Breit-Pauli (MCBP) atomic structure and collision code AUTOSTRUCTURE. Good agreement is obtained with the measurements from the Heidelberg heavy-ion Test Storage Ring facility. The Maxwellian-averaged DR rate coefficients are fitted into a simple formula for efficient dissemination of data and ease of use in plasma modeling codes.
K-shell photoabsorption cross sections are required for determining the chemical abundances of the interstellar medium. As a secondary project, K-shell photoabsorption cross sections for magnesium ions have been calculated using the Belfast R-matrix computer package.
Abdel-Azim Abdel Naby, Shahin Ahmed, "Dielectronic Recombination for Aluminum-Like Ions and Photoabsorption Cross Sections for Magnesium Ions at the K-Edge" (2010). Dissertations. 611.