NLTE opacity calculations: C-Si and C-Ge mixtures

Jarrah, W.; Benredjem, D.; Pain, Jean‐Christophe; Dubau, J.

doi:10.1016/j.hedp.2017.08.002

Cited by 6 publications

(6 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, in the latter code, configuration interaction is restricted to relativistic configurations belonging to the same non-relativistic parent configuration, which is not the case of our code described in Ref. [16]. In particular, it was recently pointed out by Li et al that configuration interaction between 1s 1 2s 2 n and 1s2p 2 n in Be-like ions was particularly strong; this may have a significant impact in the spectral range of the experiment [28] .…”

Section: Comparison To Experimentsmentioning

confidence: 80%

“…This is the IPD effect. In a previous work [16], we have taken into account the IPD effect by using the well-known formula of Stewart and Pyatt [17]. However, as shown by Hoarty et al [18], this formula as well as the alternative formula of Ecker and Kröll [19] can under or overestimate the IPD.…”

Section: Model 1 Atomic Structurementioning

confidence: 99%

“…The fact that the code described in Ref. [16] provides a better description of those structures may come from NLTE effects or from configuration interaction, which is treated only to a limited extent in SCO-RCG. Indeed, in the latter code, configuration interaction is restricted to relativistic configurations belonging to the same non-relativistic parent configuration, which is not the case of our code described in Ref.…”

Section: Comparison To Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Plasma potential and opacity calculations

Jarrah

Pain

Benredjem

2019

High Energy Density Physics

Self Cite

View full text Add to dashboard Cite

Section: Comparison To Experimentsmentioning

confidence: 80%

Section: Model 1 Atomic Structurementioning

confidence: 99%

Section: Comparison To Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Plasma potential and opacity calculations

Jarrah

Pain

Benredjem

2019

High Energy Density Physics

Self Cite

View full text Add to dashboard Cite

“…Equation ( 7) is very simple and easy to handle. For instance, it can be easily implemented in atomic-physics codes [58,59]…”

Section: Massacrier-dubau Approachmentioning

confidence: 99%

Simple electron-impact excitation cross-sections including plasma density effects

Pain,

Benredjem

2021

Preprint

View full text Add to dashboard Cite

The modeling of non-local-thermodynamic-equilibrium plasmas is crucial for many aspects of high-energy-density physics. It often requires collisional-radiative models coupled with radiativehydrodynamics simulations. Therefore, there is a strong need for fast and as accurate as possible calculations of the cross-sections and rates of the different collisional and radiative processes. We present an analytical approach for the computation of the electron-impact excitation (EIE) cross-sections in the Plane Wave Born (PWB) approximation. The formalism relies on the screened hydrogenic model. The EIE cross-section is expressed in terms of integrals, involving spherical Bessel functions, which can be calculated analytically. In order to remedy the fact that the PWB approximation is not correct at low energy (near threshold), we consider different correcting factors (Elwert-Sommerfeld, Cowan-Robb, Kilcrease-Brookes). We also investigate the role of plasma density effects such as Coulomb screening and quantum degeneracy on the EIE rate. This requires to integrate the collision strength multiplied by the Fermi-Dirac Distribution and the Pauli blocking factor. We show that, using an analytical fit often used in collisional-radiative models, the EIE rate can be calculated accurately without any numerical integration, and compare our expression with a correction factor presented in a recent work.

show abstract

“…Benredjem et al [33][34][35][36][37], this is the first comparative study between the SCO-RCG and STA opacity results. In addition to the opacity, we also compare the STA predicted ionization fractions at T e = 300 eV with the results from SCO-RCG calculation for ρ = 0.1, 0.5 and The sensitivity of the opacities to the variation of the plasma temperatures is displayed in Fig.8.…”

Section: B Opacity: Theoretical Models Comparisonmentioning

confidence: 99%

Super-transition-array calculations for synthetic spectra and opacity of high-density, high-temperature germanium plasmas

Lee¹,

Jarrah²,

Benredjem³

et al. 2020

High Energy Density Physics

Self Cite

View full text Add to dashboard Cite

The synthetic emission spectra and opacity of high-density, high-temperature germanium (Z=32) plasma from super-transition-array (STA) calculations are presented. The viability of the STA model, which is based on a statistical superconfigurations accounting approach for calculating the atomic and radiative properties, is examined by comparing and contrasting its results against the available experimental data and other theoretical calculations. First, we focus on the emission data.To model the data, the Eulerian radiation-hydrodynamics code FastRad3D is used in conjunction with STA to obtain the STA-required inputs, namely, the time-dependent temperature and density profiles of the Ge plasmas. Consequently, we find that STA results fit the experimental spectrum reasonably well, reproducing the main spectral features of 2p − 3d, 2s − 3p, and 2p − 4d transitions from the laser-heated germanium layer buried in plastic [High Energy Density Phys., 6 (2010) 105]. However, careful comparison between experimental and theoretical results in the photonenergy regions of ∼1.7 keV shows some degrees of disparity between the two. This may be due to the non-LTE effects and the presence of spatial gradients in the sample. Limitations of STA to model the experimental spectrum precisely is expected and underscoring the difficulty of the present attempts as the model assumed local thermodynamics equilibrium population dynamics.Second, we examine the STA calculated multi-frequency opacities for a broad range of Ge plasma conditions covering the L-and M-shell spectral range. Comparing with a hybrid LTE opacity code which combines the statistical super-transition-array and fine-structure methods [High Energy Density Phys., 7 (2011) 234], impressively good agreement is found between the two calculations. In addition, the sensitivity of the opacity results in various plasma temperatures and mass densities is discussed. The ionized population fraction and average ionization of the Ge plasma are also described. Comparisons of STA results in the observed spectrum and opacity are considerably close while offering the advantage of computational speed and its capability of treating hot and dense high-Z plasmas.

show abstract

NLTE opacity calculations: C-Si and C-Ge mixtures

Cited by 6 publications

References 10 publications

Plasma potential and opacity calculations

Plasma potential and opacity calculations

Simple electron-impact excitation cross-sections including plasma density effects

Super-transition-array calculations for synthetic spectra and opacity of high-density, high-temperature germanium plasmas

Contact Info

Product

Resources

About