This Is AuburnElectronic Theses and Dissertations

Non-perturbative calculations of atomic data for applications in laboratory fusion and astrophysical plasmas




Wu, Di

Type of Degree





Results are presented for non-perturbative quantal calculations of atomic data for application in laboratory fusion and astrophysical plasmas. One of the key issues in laboratory fusion plasmas is the accurate modeling of impurity transport of wall material as it is ablated into the plasma. In support of experiments at Wisconsin-Madison, new ionization cross sections for Al and Al2+ were generated. These are supplemented with previous non- perturbative calculations for Al+ and new distorted-wave calculations for the remaining ions. This new ionization dataset is compared with previous semi-empirical calculations and literature values, and the likely implications for impurity transport modeling are discussed. For the application to astrophysical plasmas, a recent development in supernova remnant X-ray emission is considered. The emission from less abundant iron-peak elements (Mn, Cr, Co and Ni) from supernova remnant plasmas has been detected and represents a potentially useful diagnostic opportunity to determining elemental abundances in these plasmas, and to test current supernova models. However, the studies are currently hampered by a lack of K-shell atomic data for many of the Fe-peak elements. Thus, R-matrix calculations for the electron-impact excitation of Ne-like Cr, Mn, Fe, Co and Ni ions are calculated. Collisional- radiative modeling is used to produce emissivities for each of these ions. The results are compared with X-ray spectra from the Tycho supernova remnant plasma, and abundances for Cr and Mn are derived. Evidence is presented that the line commonly identified as Fe Kβ is blended with another line, possibly the Co Kα feature. To assess the possibility that this line originates from a neighboring charge state of Fe, new atomic data for F-like Fe-peak elements are produced. The future direction of this work, and the potential applications of the data are also discussed.