The Virtual Atomic and Molecular Data Centre (VAMDC, http://www.vamdc.eu) is a European Union funded collaboration between groups involved in the generation, evaluation, and use of atomic and molecular data. VAMDC aims to build a secure, documented, flexible and interoperable e-science environment-based interface to existing atomic and molecular data. The project will cover establishing the core consortium, the development and deployment of the infrastructure and the development of interfaces to the existing atomic and molecular databases. It will also provide a forum for training potential users and dissemination of expertise worldwide. This review describes the scope of the VAMDC project; it provides a survey of the atomic and molecular data sets that will be included plus a discussion of how they will be integrated. Some applications of these data are also discussed.

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Virtual Atomic and Molecular Data Centre

Advances in NLTE modeling for integrated simulations

Hybrid atomic models for spectroscopic plasma diagnostics

The role of a detailed configuration accounting (DCA) atomic physics package in explaining the energy balance in ignition-scale hohlraums

The last few years have seen significant progress in constructing the atomic models required for non-local thermodynamic equilibrium (NLTE) simulations. Along with this has come an increased understanding of the requirements for accurately modeling the ionization balance, energy content and radiative properties of different elements for a wide range of densities and temperatures. Much of this progress is the result of a series of workshops dedicated to comparing the results from different codes and computational approaches applied to a series of test problems. The results of these workshops emphasized the importance of atomic model completeness, especially in doubly excited states and autoionization transitions, to calculating ionization balance, and the importance of accurate, detailed atomic data to producing reliable spectra. We describe a simple screened-hydrogenic model that calculates NLTE ionization balance with surprising accuracy, at a low enough computational cost for routine use in radiation-hydrodynamics codes. The model incorporates term splitting, {Delta}n = 0 transitions, and approximate UTA widths for spectral calculations, with results comparable to those of much more detailed codes. Simulations done with this model have been increasingly successful at matching experimental data for laser-driven systems and hohlraums. Accurate and efficient atomic models are just one requirement for integrated NLTE simulations. Coupling the atomic kinetics to hydrodynamics and radiation transport constrains both discretizations and algorithms to retain energy conservation, accuracy and stability. In particular, the strong coupling between radiation and populations can require either very short timesteps or significantly modified radiation transport algorithms to account for NLTE material response. Considerations such as these continue to provide challenges for NLTE simulations.

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Advances in NLTE Modeling for Integrated Simulations

Review of the 4th NLTE Code Comparison Workshop

Comparison of plasma population kinetics codes, which has become an important tool for their testing and verification, was the subject of the third Non-LTE Code Comparison Workshop held at the National Institute of Standards and Technology in December 2003. The motivations for the workshop are presented here, together with its technical organization. The cases studied range from carbon to gold, and include both steady-state and time-dependent calculations. The set of results represents the current capabilities in kinetics modeling, and illustrates the effectiveness of this workshop approach to code comparisons. It was found that good agreement between codes and with experiments is observed near closed shells, but significant differences exist otherwise, or when density effects are important. On a more general level, we discuss how to meaningfully compare kinetics data. We conclude with plans for the next workshop and for a kinetics database.

C Bowen

Papers

Review of the 4th NLTE Code Comparison Workshop

Comparing plasma population kinetics codes: Review of the NLTE-3 Kinetics Workshop