Opacity profiles in inertial confinement fusion plasmas

Abstract

The opacity is an important issue in the knowledge of radiative properties of ICF and astrophysical plasmas. In this work we present the opacity of dopants embedded in the ablator of some ICF capsules. The silicon is used as dopant and we are interested in C+Si mixtures. We have used two methods to calculate the opacity of C+Si. The first one involves a detailed line shape calculation in which the atomic database is provided by a MCDF code. The lineshape code PPP is then adapted to the calculation of opacity profiles. Almost all spectral broadening effects, including Zeeman splitting and Stark effect, are taken into account. This method is able to provide accurate opacity spectra but becomes rapidly prohibitive when the number of lines is large. To account for many ionic stages and thousands of lines, a second method -hybrid method- is prefered. This method combines detailed-line and statistical calculations. In the spectral regions where the lines are sufficiently separated and the number of radiative transitions is moderate, the hybrid method performs detailed calculations. When the number of transitions is very large and most of them merge in broad structures due to line broadening, the hybrid method performs statistical calculations.