Radiative opacity of gold plasmas studied by a detailed level-accounting method

Abstract

There are systematic discrepancies unexplained so far between theory and experiment for opacities of mid- and high- Z plasmas. To address this issue, we investigated the radiative opacity of gold plasmas by using a detailed level-accounting (DLA) method, in which various physical effects can be taken into account. In this work, we studied in detail the effects of core-valence electron correlation and linewidth on the opacity of gold plasmas. Our DLA results correctly explain the relative intensity of the two strong absorption peaks located near the photon energies of 70 and 80eV , which was experimentally observed by Eidmann [Europhys. Lett. 44, 459 (1998)]. Meanwhile, the DLA results showed that effects of saturation for the strong individual lines are evident in the transmission spectrum.

Plasma screening effects on the atomic structure and radiative opacity of dense carbon plasmas based on the DLA model

“…The details of the DLA model can be found elsewhere [10,11], here we only give a brief outline in the following. For an LTE plasma with temperature T and mass density r (or electron density), the radiative opacity at photon energy hn is given by…”

“…During past few decades, theoretical models such as unresolved transition arrays (UTA) [3], super transition arrays (STA) [4,5], average atom (AA) [6], detailed term accounting (DTA) [7e10] and detailed level accounting (DLA) models [11] were developed to investigate the radiative opacity of plasmas. In dense plasmas, the interactions of the charged particles are usually screened by the surrounding ions and electrons, resulting in changes of energy levels, electron transition properties and photoionization cross sections when compared with free ions in vacuum.…”

K-shell energy levels and radiative rates for transitions in Si ix

“…Their results confirmed that there are differences with the results from the database (Kaastra & Mewe 1993), and showed that these fluorescence yields are strongly LSJ dependent. Zeng & Yuan (2006) have shown that inclusion of CI from the excited configurations can improve the accuracy of the calculations of the atomic data, such as energy levels and oscillation strengths.…”

Opacity Studies of Silicon in Radiatively Heated Plasma

“…Various models have been used to simulate such experimental results, for example, the unresolved transition array (Bauche & Bauche-Arnoult 1996), super-transition arrays (Bar-Shalom et al 1989, and average-atom (Yuan 2002) and detailed term accounting models (Abdallah & Clark 1991;Zeng et al 2000;Zeng & Yuan 2002;Jin et al 2004). We note that the averageatom model cannot reproduce fine spectral structure because of the simplifications it employs, whereas the detailed level accounting (DLA) model can deal with line saturation effects more accurately, although it is more time-consuming (Zeng & Yuan 2006).…”

“…We note that the averageatom model cannot reproduce fine spectral structure because of the simplifications it employs, whereas the detailed level accounting (DLA) model can deal with line saturation effects more accurately, although it is more time-consuming (Zeng & Yuan 2006).…”