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Title: Higher-order microfield effects on spectral-line broadening in dense plasmas

Miscellaneous ·
OSTI ID:5188095

Radiating atoms in dense plasmas are highly affected by their local plasma environment. The author examines the effect of this environment on hydrogenic radiators by using an atomic wave function basis set that is itself a function of the plasma electric microfield for the calculation of spectral line profiles. His theoretical development includes the effect of static ion perturbers up to the quadrupole term in the multipole expansion of the radiator-perturbing ion interaction, as well as dynamic electron broadening up to second order in the radiator-perturbing electron interaction. Effects due to the presence of the uniform ion-electric field are treated exactly within this framework, and the field gradient is then treated as a perturbation by inclusion of the ion-quadrupole term. He employs a basis set for the representation of the upper state of the transition that includes states of principle quantum number n as well as n + 1 to allow for the field mixing of these two manifolds. The ion-quadrupole effect is treated in a new way that includes ion correlations by using a renormalized independent-particle model for the perturbing ions. He also presents a preliminary assessment of the importance of field ionization on the spectral line shapes. His results are compared with previously reported calculations using field independent matrix elements, neglect of possible field ionization and the independent-particle model of the ion-quadrupole effect. Hence, he is able to identify the most important effects that arise from the use of the field dependent basis set. These comparisons also allow him to examine the importance of ion correlations when determining the ion-quadrupole effect.

Research Organization:
Florida Univ., Gainesville, FL (United States)
OSTI ID:
5188095
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English