Escape factors for Stark-broadened line profiles

Mancini, R. C.; Joyce, Robert; Hooper, C. F.

doi:10.1088/0022-3700/20/13/011

Cited by 62 publications

(38 citation statements)

References 7 publications

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“…We used the Stewart and Pyatt model [16] for continuum lowering effects and the escape factor approximation to account for radiation transport effects on the populations [17] . The spectral emissivity and opacity are computed from the calculated populations including detailed Stark line profiles computed by MERL [18] .…”

Section: Spectral Modelmentioning

confidence: 99%

An important criterion for reliable multi-monochromatic x-ray imager diagnostics and its impact on the reconstructed images

Nagayama

Mancini

Mayes

et al. 2015

High Pow Laser Sci Eng

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Temperature and density asymmetry diagnosis is critical to advance inertial confinement fusion (ICF) science. A multimonochromatic x-ray imager, MMI, records the spectral signature from an ICF implosion core with time resolution, 2D spatial resolution and spectral resolution. While narrow-band images and 2D space-resolved spectra from the MMI data constrain the temperature and the density spatial structure of the core, the accuracy of the images and the spectra highly depends on the quality of the MMI data and the processing tools. Here, we synthetically investigate the criterion for reliable MMI diagnostics and its effects on the accuracy of the reconstructed images. The pinhole array tilt determines the object spatial sampling efficiency and the minimum reconstruction width, w. When the spectral width associated with w is significantly narrower than the spectral linewidth, the line images reconstructed from the MMI data become reliable. The MMI setup has to be optimized for every application to meet this criterion for reliable ICF diagnostics.

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Section: Spectral Modelmentioning

confidence: 99%

An important criterion for reliable multi-monochromatic x-ray imager diagnostics and its impact on the reconstructed images

Nagayama

Mancini

Mayes

et al. 2015

High Pow Laser Sci Eng

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“…Continuum lowering is particularly important for determining the ionization balance of the compressed shell and thus the details of the contributions of photoionization and inverse bremsstrahlung to the total opacity of the compressed shell. Radiation transport effects on level population kinetics were considered via escape factors [27]. For the plasma conditions of these implosions, characteristic optical depth values τ for argon line transitions are τ ∼ 0.5 for the Heγ and Lyγ lines, τ ∼ 1 for Heβ and Lyβ, and τ > 10 for Heα and Lyα.…”

Section: Implosion Experiments and Spectroscopic Modelmentioning

confidence: 99%

Measurements of core and compressed-shell temperature and density conditions in thick-wall target implosions at the OMEGA laser facility

et al. 2011

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A spectroscopic method is discussed to measure core and compressed shell conditions in thickwall plastic-shell implosions filled with deuterium and a tracer amount of argon. Simultaneous observation over a broad photon energy range of the argon line emission and the attenuation and self-emission effects of the compressed shell confining the core yields enough information to extract average temperature and density conditions in both core and compressed shell. The spectroscopic analysis also provides an estimate of the target areal density which is an important characteristic of inertial confinement fusion implosions.

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“…A known approximation consisting of taking the cross-section of collisional excitation to calculate the electron capture cross-section has been properly adapted to work in a DCA scheme. The escape factor formalism [7] for the basic geometries -plane, cylindric and spherical-is used to take into account the bound-bound opacity effects. It also should be mentioned that ABAKO incorporates a new technique for the line transport [8].…”

Section: The Collisional-radiative Modulementioning

confidence: 99%

ABAKO: A new code for population kinetics and radiative properties of plasmas under NLTE conditions

Florido¹,

Rodríguez²,

Gil³

et al. 2008

J. Phys.: Conf. Ser.

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Abstract. In this work we present ABAKO, a new computational code based on analytical models and developed to study the population kinetics of steady-state plasmas. The tool ABAKO can be applied to low-to-high Z ions under a wide range of laboratory plasma conditions: coronal, LTE or NLTE, optically thin or thick plasmas. Autoionizing states are explicitly included. The results obtained with ABAKO are competitive with more elaborated, but also time-consuming codes. Our code provides satisfactory charge state distributions (CSD) and reasonable estimations of spectroscopic observables of high-Z plasmas, as it can be seen through comparison with experimental data. IntroductionEfforts continue to be made in the modeling of plasmas in non local-thermodynamic-equilibrium (NLTE). Many systematic studies have been made to assess the accuracy of such modeling attempts and detect areas needing improvements. Recent NLTE workshops [1,2] have focused on comparisons for specific cases between collisional-radiative (CR) codes developed by diverse research groups. On the other hand, the ability to reproduce experimental data is the most valuable test for any CR model, but clean experiments are very difficult to perform and there exist only few measurements that could be used as benchmark cases for the validation of computational codes. In summary, further investigation into population kinetics of NLTE plasmas is necessary and any progress for providing a better understanding of the underlying physics will be welcomed.In this work we present ABAKO, Analytical expressions BAsed Kinetics cOde, a new CR model to determine the population distribution of atomic levels and radiative properties of steady-state plasmas. The versatility is a remarkable characteristic in ABAKO. It can be applied to low-to-high Z ions under a wide range of laboratory plasma conditions: coronal, LTE or NLTE, optically thin or thick plasmas. On the other hand, a special care was taken during the ABAKO development to achieve an optimal equilibrium between accuracy and computational cost. ABAKO assembles a set of simple analytical models which yield a substantial saving of computational requirements, but providing satisfactory results in relation to those ones obtained from more sophisticated codes and experimental data.

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Escape factors for Stark-broadened line profiles

Cited by 62 publications

References 7 publications

An important criterion for reliable multi-monochromatic x-ray imager diagnostics and its impact on the reconstructed images

An important criterion for reliable multi-monochromatic x-ray imager diagnostics and its impact on the reconstructed images

Measurements of core and compressed-shell temperature and density conditions in thick-wall target implosions at the OMEGA laser facility

ABAKO: A new code for population kinetics and radiative properties of plasmas under NLTE conditions

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