J. Colgan (*), D. P. Kilcrease (*), N. H. Magee, Jr. (*), J. Abdallah, Jr. (*), M. E. Sherrill (*), C. J. Fontes (#), H. L. Zhang (#)
(*) Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. (#) Computational Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
We present new calculations of local-thermodynamic-equilibrium (LTE) light element opacities from the Los Alamos ATOMIC code . ATOMIC is a multi-purpose code that can generate LTE or non-LTE quantities of interest at various levels of approximation. Our calculations represent a systematic improvement over previous Los Alamos opacity calculations using the LEDCOP legacy code .
The ATOMIC code uses ab-initio atomic structure data computed from the CATS code, which is based on Cowan’s atomic structure codes , and photoionization cross section data computed from the Los Alamos ionization code GIPPER. ATOMIC also incorporates a new equation-of-state (EOS) model based on the chemical picture . Several of the physics packages used in LEDCOP have been modified and incorporated into ATOMIC, such as Stark broadening and free-free absorption. Our new calculations are made for elements with Z= 1-10, and for a wide range of temperatures and densities.
Selected comparisons of our new opacity calculations with several other sets of calculations will be presented at the meeting, to highlight sensitivities to the quality of the atomic data and to the EOS model used. In particular, we will present detailed comparisons of our Rosseland mean opacity calculations with Opacity Project (OP)  and OPAL calculations  for hydrogen and helium.
The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396.
Poster presented at the 17th International Conference on Atomic Processes in Plasmas, Queen’s University Belfast, 19-22 July 2011.
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