Lumped versus detailed accounting for dielectronic recombination processes in non-LTE kinetics of a copper pinch*

The NRL DZAPP code has been used to simulate a copper z pinch. DZAPP couples 1D MHD with non-LTE level kinetics and radiation transport, and incorporates a transmission line circuit to drive the load. The non-LTE level kinetics in DZAPP is solved using an atomic model that includes dielectronic recombination as an effective lumped ground-to-ground rate with radiative transport equation using a frequency averaged probability-of-escape method for the lines and edges. The plasma profiles of density and internal energy will also be post-processed with the NRL code Drachma II. The non-LTE model in Drachma II is more general. First, the doubly excited state populations are explicitly carried in the level kinetics. Consequently, the satellite lines are inherently generated in the synthetic spectrum. Second, line overlap is automatically included because of the treatment of multi-frequency radiation transport. The resulting differences in the ionization balance and synthetic spectra between the two approaches will be presented for the L- and K-shell of copper.