Ionization competition effects on population distribution and radiative opacity of mixture plasmas

Li, Yongjun; Cheng, Guangquan; Tian, Qinyun; Zeng, Jiaolong; Yuan, Jing

doi:10.1063/1.4935298

Cited by 3 publications

(5 citation statements)

References 42 publications

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“…The ionization balance of mixture plasma can be determined by including all pure elements in the Saha equation (Li et al 2015).…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…The ionization competition effect (Li et al 2015) between C and H is considered in the solution of the Saha equation for the CH-mixture plasma. Practical calculations indicate that this effect is small in the experimental sample (Kraus et al 2016) and under the given plasma conditions; however, the screening of C ions contributed by the free electrons of H atoms must be considered.…”

Section: Analysis and Explanation Of A Recent Experimentsmentioning

confidence: 99%

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Ionization potential depression and ionization balance in dense carbon plasma under solar and stellar interior conditions

Zeng

Hou

et al. 2020

A&A

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Recent quantitative experiments on the ionization potential depression (IPD) in dense plasma show that the observational results are difficult to explain with the widely used analytical models for plasma screening. Here, we investigate the effect of plasma screening on the IPD and ionization balance of dense carbon plasma under solar and stellar interior conditions using our developed consistent nonanalytical model. The screening potential can be primarily attributed to the free electrons in the plasma and is determined by the microspace distribution of these free electrons. The ionization balance is determined by solving the Saha equation, including the effect of IPD. The predicted IPD and average ionization degree are larger than those obtained using the Stewart–Pyatt model for mass densities that are greater than 3.0 g cm−3. Under solar interior conditions, our results are in better agreement with the Ecker–Kröll model at electron temperatures and densities lower than 250 eV and 2.1 × 1023 cm−3 and in the best agreement with the ion-sphere model at 303 eV and 4.3 × 1023 cm−3. Finally, our results are compared with those obtained via a recent experiment on a CH-mixture plasma that has been compressed six times. The predicted average ionization degree of C in a CH mixture agrees better with the experiment than the Stewart–Pyatt and Thomas–Fermi models when the screening from free electrons contributed by hydrogen atoms is included. Our results provide useful information concerning the ionization balance and can be applied to investigate the opacity and equations of state for dense plasma under the solar and stellar interior conditions.

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“…The ionization balance of mixture plasma can be determined by including all pure elements in the Saha equation (Li et al 2015).…”

Section: Theoretical Methodsmentioning

confidence: 99%

Section: Analysis and Explanation Of A Recent Experimentsmentioning

confidence: 99%

Ionization potential depression and ionization balance in dense carbon plasma under solar and stellar interior conditions

Zeng

Hou

et al. 2020

A&A

Self Cite

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“…The measure was in fact performed on a plasma of SiO 2 . However, the ionization competition between oxygen and silicon in the mixture was studied using an isolated-ion detailed model with Stewart-Pyatt continuum lowering [162]. Its effect on the populations of silicon was shown to be rather weak.…”

Section: Fluctuations Around the Average Atomic State And The Need Fo...mentioning

confidence: 99%

“…This is due to the accounting for the induced field in the homogeneous plasma response, while disregarding collisions, which would saturate this resonant behavior. If one takes the factor in the ω >> ω P limit, then the first term on the right-hand side of Equation ( 171) may be recovered from Equation (162). The second term is purely due to the accounting for the induced potential, that is, for self-consistency in the dynamic behavior of the displacedelectron density.…”

Section: Self-consistent Linear Responsementioning

confidence: 99%

Atomic Models of Dense Plasmas, Applications, and Current Challenges

Piron

2024

Atoms

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Modeling plasmas in terms of atoms or ions is theoretically appealing for several reasons. When it is relevant, the notion of atom or ion in a plasma provides us with an interpretation scheme of the plasma’s internal functioning. From the standpoint of quantitative estimation of plasma properties, atomic models of plasma allow one to extend many theoretical tools of atomic physics to plasmas. This notably includes the statistical approaches to the detailed accounting for excited states, or the collisional-radiative modeling of non-equilibrium plasmas, which is based on the notion of atomic processes. This paper is focused on the theoretical challenges raised by the atomic modeling of dense, non-ideal plasmas. It is intended to give a synthetic and pedagogical view on the evolution of ideas in the field, with an accent on the theoretical consistency issues, rather than an exhaustive review of models and experimental benchmarks. First we make a brief, non-exhaustive review of atomic models of plasmas, from ideal plasmas to strongly-coupled and pressure-ionized plasmas. We discuss the limitations of these models and pinpoint some open problems in the field of atomic modeling of plasmas. We then address the peculiarities of atomic processes in dense plasmas and point out some specific issues relative to the calculation of their cross-sections. In particular, we discuss the modeling of fluctuations, the accounting for channel mixing and collective phenomena in the photoabsorption, or the impact of pressure ionization on collisional processes.

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“…Furthermore, the different components in the mixture are also coupled through the CL since in the formalism adopted in our CRSS model this one depends on the average ionization of the mixture. The coupling through the common free electron density and the CL takes into account the effect of the ionization competition between different atomic species on the population distribution and radiative properties [44] that might modify these properties compared with pure matters. For the experiment analyzed in this work, mixtures of Ar and Al in different proportions can be found and our procedure to perform the simulations of their microscopic properties was as follows: for a given density of matter and electron temperature of the profiles, provided by the radiative-hydrodynamic simulation using the GORGON code, we carried out an initial estimation of the total number electron density.…”

Section: B Calculation Of Plasma Atomic Level Populationsmentioning

confidence: 99%

Influence of atomic kinetics in the simulation of plasma microscopic properties and thermal instabilities for radiative bow shock experiments

et al. 2017

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Numerical simulations of laboratory astrophysics experiments on plasma flows require plasma microscopic properties that are obtained by means of an atomic kinetic model. This fact implies a careful choice of the most suitable model for the experiment under analysis. Otherwise, the calculations could lead to inaccurate results and inappropriate conclusions. First, a study of the validity of the local thermodynamic equilibrium in the calculation of the average ionization, mean radiative properties, and cooling times of argon plasmas in a range of plasma conditions of interest in laboratory astrophysics experiments on radiative shocks is performed in this work. In the second part, we have made an analysis of the influence of the atomic kinetic model used to calculate plasma microscopic properties of experiments carried out on MAGPIE on radiative bow shocks propagating in argon. The models considered were developed assuming both local and nonlocal thermodynamic equilibrium and, for the latter situation, we have considered in the kinetic model different effects such as external radiation field and plasma mixture. The microscopic properties studied were the average ionization, the charge state distributions, the monochromatic opacities and emissivities, the Planck mean opacity, and the radiative power loss. The microscopic study was made as a postprocess of a radiative-hydrodynamic simulation of the experiment. We have also performed a theoretical analysis of the influence of these atomic kinetic models in the criteria for the onset possibility of thermal instabilities due to radiative cooling in those experiments in which small structures were experimentally observed in the bow shock that could be due to this kind of instability.

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Ionization competition effects on population distribution and radiative opacity of mixture plasmas

Cited by 3 publications

References 42 publications

Ionization potential depression and ionization balance in dense carbon plasma under solar and stellar interior conditions

Ionization potential depression and ionization balance in dense carbon plasma under solar and stellar interior conditions

Atomic Models of Dense Plasmas, Applications, and Current Challenges

Influence of atomic kinetics in the simulation of plasma microscopic properties and thermal instabilities for radiative bow shock experiments

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