Open Access
Advances in NLTE Modeling for Integrated Simulations
Howard A. Scott,Stephanie Hansen,Stephanie Hansen +2 more
- Vol. 6
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TLDR
In this paper, a simple screened-hydrogenic model was proposed to calculate ionization balance with surprising accuracy, at a low enough computational cost for routine use in radiation-hydrodynamics codes.Abstract:
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.read more
Citations
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Experimental and simulation studies on gold bubble movement in gas-filled hohlraums
Liang Guo,Xin Li,Xufei Xie,Bo Deng,Xiaohua Jiang,Sanwei Li,Zhichao Li,Keli Deng,Wang Qiangqiang,Zhurong Cao,Peng Song,Huabin Du,Yimeng Yang,Xinsen Che,Lifei Hou,Zha Weiyi,Xu Tao,Shenye Liu,Chunyang Zheng,Wudi Zheng,Yongkun Ding,Dong Yang,Feng Wang,Jiamin Yang,Shaoen Jiang,Baohan Zhang +25 more
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Study on laser-irradiated Au plasmas by detailed configuration accounting atomic physics
TL;DR: In this paper, the authors coupled the one-dimensional multi-group radiation hydrodynamic code RDMG with the MBDCA atomic physics package, which uses the Matrix-Block Method to solve the coupled rate equations of the Detailed Configuration Accounting (DCA) non-LTE model, and applied the coupled code with different flux limiters to simulate a laser-irradiated CH-tamped Au disk experiment at the SGII laser facility.
Creating and Probing Extreme States of Materials : From Gases and Clusters to Biosamples and Solids
TL;DR: Free-electron lasers provide high intensity pulses with femtosecond duration and are ideal tools in the investigation of ultrafast processes in materials as mentioned in this paper, and they can be used in any material with such pulses.
Journal ArticleDOI
Rayleigh–Taylor mixing may account for the position anomaly in NIF microdot spectroscopy experiments
TL;DR: Barrios et al. as discussed by the authors showed that the position discrepancy can be explained by a Rayleigh-Taylor mixing of the dot into the ablator as it expands in the Hohlraum.
Journal ArticleDOI
Measurements and non-local thermodynamic equilibrium modeling of mid-Z plasma emission
L. Jacquet,M. Primout,P. Kaiser,J. F. Clouët,F. Girard,B. Villette,Charles Reverdin,G. Oudot +7 more
TL;DR: In this article, the x-ray yields from laser-irradiated thin foils of iron, copper, zinc, and germanium have been measured in the soft and multi-keV X-ray ranges at the OMEGA laser at the Laboratory for Laser Energetics.
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