State Department and Related Agencies FY1998 Appropriations (open access)

State Department and Related Agencies FY1998 Appropriations

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Date: December 10, 1997
Creator: Epstein, Susan B.
System: The UNT Digital Library
Fiscal Year 1998 report theoretical studies of ground energy coupling (open access)

Fiscal Year 1998 report theoretical studies of ground energy coupling

A method for calculating the redistribution of resonance radiation in hot, dense plasmas is developed by extending the Frequency Fluctuation Model (FFM). This paper is devoted to a brief review of lineshape theory in the linear response approximation, and an introduction to the FFM approach to the modeling of lineshapes in plasmas. This discussion begins with a consideration of the spectral lines emitted by complex ions in plasmas. As is well known, the lineshape is determined by the time- dependent coupling of the ion with the plasma environment. This plasma-emitter interaction, leads to Stark broadening of the spectral lines, and traditionally has been considered in the approximation which treats the ef&@ of the electrons on the emitting ion in the impact limit while the ionic perturbation is� taken to be quasi-static. In this approximation, the time dependence of the perturbation has been eliminated, resulting in a spectral line shape that has purely homogeneous and inhomogeneous contributions and that is described by a simple sum of independent electron imp� act broadened static components. In order to clarify the concepts presented, examples of radiative redistribution functions for simple cases are presented. Included is an example of an X-ray laser pumped system which …
Date: December 10, 1998
Creator: Klein, L.
System: The UNT Digital Library