Hybrid atomic models for spectroscopic plasma diagnostics

Hansen, Stephanie B.; Bauche, J.; Bauche‐Arnoult, C.; Gu, Minfeng

doi:10.1016/j.hedp.2007.02.032

Cited by 158 publications

(97 citation statements)

References 21 publications

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“…The detailed spectrum was calculated with SCRAM, using hybrid atomic data [14] constructed from a combination of fine structure and UTA data from FAC, supplemented with the extended screened-hydrogenic model (including satellite shifts). The agreement is excellent, both in mean ionization <Z> and in the emission spectrum.…”

Section: Extensions To Atomic Models For Radiation Transportmentioning

confidence: 99%

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Advances in NLTE modeling for integrated simulations

Scott

Hansen

2010

High Energy Density Physics

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187

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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, 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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Section: Extensions To Atomic Models For Radiation Transportmentioning

confidence: 99%

“…The two codes produce comparable atomic data, and results presented from either code will be labeled "DCA". For comparisons with a more detailed code (beyond those done as part of the NLTE workshops) we use SCRAM [13,14], with atomic data generated by FAC [3].…”

Section: Introductionmentioning

confidence: 99%

Advances in NLTE modeling for integrated simulations

Scott

Hansen

2010

High Energy Density Physics

Self Cite

187

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“…We have used synthetic Ni spectra generated by the collisional-radiative model SCRAM [12] to diagnose the plasma conditions. Data from the flexible atomic code (FAC) [13] for neutral to H-like Ni was used to construct a complete and accurate set of levels and rate data based on fine-structure/unresolved transition array (UTA) hybrid level structure [12].…”

mentioning

confidence: 99%

“…Data from the flexible atomic code (FAC) [13] for neutral to H-like Ni was used to construct a complete and accurate set of levels and rate data based on fine-structure/unresolved transition array (UTA) hybrid level structure [12]. The hot electron fraction in the solid target was estimated to be <1%, based on an upper-limit conversion efficiency of laser light of 50% [14] and a 70 m hot electron injection area corresponding to the K spot diameter measured on thin Cu targets in this experiment.…”

mentioning

confidence: 99%

Laser Heating of Solid Matter by Light-Pressure-Driven Shocks at Ultrarelativistic Intensities

Akli

Hansen²,

Kemp³

et al. 2008

Phys. Rev. Lett.

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The heating of solid targets irradiated by 5 10 20 Wcm ÿ2 , 0.8 ps, 1:05 m wavelength laser light is studied by x-ray spectroscopy of the K-shell emission from thin layers of Ni, Mo, and V. A surface layer is heated to 5 keV with an axial temperature gradient of 0:6 m scale length. Images of Ni Ly show the hot region has 25 m diameter. These data are consistent with collisional particle-in-cell simulations using preformed plasma density profiles from hydrodynamic modeling which show that the >100 G bar light pressure compresses the preformed plasma and drives a shock into the solid, heating a thin layer.

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“…OP [42,43] 0.59 R-matrix [75,76] 0.51 ATOMIC [39,40] 0.60 OPAS [82][83][84] 0.70 SCO-RCG [17] 0.64 SCRAM [85] 0.77 TOPAZ [86,87] 0.62 Cold [72] 0.75…”

Section: Source κ R Relative To Experimentsmentioning

confidence: 99%

Detailed Opacity Calculations for Astrophysical Applications

Pain

Gilleron

Comet

2017

Atoms

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Nowadays, several opacity codes are able to provide data for stellar structure models, but the computed opacities may show significant differences. In this work, we present state-of-the-art precise spectral opacity calculations, illustrated by stellar applications. The essential role of laboratory experiments to check the quality of the computed data is underlined. We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as well as X-ray emission spectroscopy experiments involving hot dense plasmas produced by ultra-high-intensity laser irradiation. The measured spectra are systematically compared with the fine-structure opacity code SCO-RCG. The focus is on iron, due to its crucial role in understanding asteroseismic observations of β Cephei-type and Slowly Pulsating B stars, as well as of the Sun. For instance, in β Cephei-type stars, the iron-group opacity peak excites acoustic modes through the "kappa-mechanism". Particular attention is paid to the higher-than-predicted iron opacity measured at the Sandia Z-machine at solar interior conditions. We discuss some theoretical aspects such as density effects, photo-ionization, autoionization or the "filling-the-gap" effect of highly excited states.

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Hybrid atomic models for spectroscopic plasma diagnostics

Cited by 158 publications

References 21 publications

Advances in NLTE modeling for integrated simulations

Advances in NLTE modeling for integrated simulations

Laser Heating of Solid Matter by Light-Pressure-Driven Shocks at Ultrarelativistic Intensities

Detailed Opacity Calculations for Astrophysical Applications

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