A new algorithm for solving non-LTE atomic populations in hot plasmas
Abstract
Most ICF plasmas are not in Local Thermodynamic Equilibrium(LTE) because of gradients of temperature and radiation losses. Therefore, rate equations have to be set and solved for the level populations of atomic ions. These can be fine structure levels, configurations, or superconfigurations, depending on the complexity of the spectra. The rate equations to be solved often involve tens of thousands of levels. We present here an algorithm which is more physical than the commonly used biconjugate gradient[1]. The populations are factorized into total ion and reduced level populations. This yields a double linearized iterative scheme. Global rates are iteratively refined, so it is possible to quickly converge on average charge Z*. Results and comparison with other methods will be shown. Work supported by the USDOE under a contract with Naval Research Laboratory, Laser Plasma Branch. [1] W. H. Press, B. P. Flannery, S. A. Teukolsky et al., Numerical Recipes in Fortran 77 , 2nd ed. (Cambridge University Press, Cambridge, UK, 1996).
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 2004
- Bibcode:
- 2004APS..DPPEP1016K