Electron localization enhanced photon absorption for the missing opacity in solar interior

Zeng, Jiaolong; Cheng, Guangquan; Liu, Pengfei; Li, Yongjun; Meng, CongSen; Hou, Yuxin; Kang, Dongdong; Yuan, Jianmin

doi:10.1007/s11433-021-1812-1

Cited by 10 publications

(4 citation statements)

References 64 publications

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“…For an isolated ion of nuclear number Z with N electrons (

refers to an atom), the atomic properties and wave functions are determined by solving the Dirac equation using a consistent field method [ 60 , 61 ]. In dense plasma, which is characterized by electron temperature T and density

, both the bound and continuum electrons of the ion feel a plasma screening potential

that originates from the interaction with surrounding electrons and ions in the plasma [ 62 , 63 , 64 , 65 , 66 ]:

where

defines the radius of the ion sphere. The free-electron density distribution

follows Fermi–Dirac statistics, which are obtained from the ionization equilibrium equation of the plasma.…”

Section: Methodsmentioning

confidence: 99%

The Strong Enhancement of Electron-Impact Ionization Processes in Dense Plasma by Transient Spatial Localization

Zeng

Wang

Liu

et al. 2022

IJMS

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Recent experiments have observed much higher electron–ion collisional ionization cross sections and rates in dense plasmas than predicted by the current standard atomic collision theory, including the plasma screening effect. We suggest that the use of (distorted) plane waves for incident and scattered electrons is not adequate to describe the dissipation that occurs during the ionization event. Random collisions with free electrons and ions in plasma cause electron matter waves to lose their phase, which results in the partial decoherence of incident and scattered electrons. Such a plasma-induced transient spatial localization of the continuum electron states significantly modifies the wave functions of continuum electrons, resulting in a strong enhancement of the electron–ion collisional ionization of ions in plasma compared to isolated ions. Here, we develop a theoretical formulation to calculate the differential and integral cross sections by incorporating the effects of plasma screening and transient spatial localization. The approach is then used to investigate the electron-impact ionization of ions in solid-density magnesium plasma, yielding results that are consistent with experiments. In dense plasma, the correlation of continuum electron energies is modified, and the integral cross sections and rates increase considerably. For the ionization of Mg9+e+1s22s2S→1s21S+2e, the ionization cross sections increase several-fold, and the rates increase by one order of magnitude. Our findings provide new insight into collisional ionization and three-body recombination and may aid investigations of the transport properties and nonequilibrium evolution of dense plasma.

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“…For an isolated ion of nuclear number Z with N electrons (

, both the bound and continuum electrons of the ion feel a plasma screening potential

that originates from the interaction with surrounding electrons and ions in the plasma [ 62 , 63 , 64 , 65 , 66 ]:

where

defines the radius of the ion sphere. The free-electron density distribution

follows Fermi–Dirac statistics, which are obtained from the ionization equilibrium equation of the plasma.…”

Section: Methodsmentioning

confidence: 99%

The Strong Enhancement of Electron-Impact Ionization Processes in Dense Plasma by Transient Spatial Localization

Zeng

Wang

Liu

et al. 2022

IJMS

Self Cite

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“…There have been a number of experimental studies on 'warm dense matter' created in solid targets irradiated by high-intensity lasers [34,35] and exotic phenomena such as Kα resonance fluorescence [36][37][38][39]. These are accompanied by DW and atomic structure calculations using non-perturbative methods showing an enhancement of photoionization and collisional ionization rates and opacity [40]. The HED plasma effects are more readily incorporated in such models as they are simpler than RMOP calculations and enable more wide ranging studies (viz.…”

Section: High-energy-density (Hed) Plasmasmentioning

confidence: 99%

R-Matrix calculations for opacities: II. Photoionization and oscillator strengths of iron ions Fe xvii, Fe xviii and Fe xix

Nahar,

Zhao,

Eissner

et al. 2024

J. Phys. B: At. Mol. Opt. Phys.

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Iron is the dominant heavy element that plays an important role in radiation transport in stellar interiors. Owing to its abundance and large number of bound levels and transitions, iron ions determine the opacity more than any other astrophysically abundant element. A few iron ions constitute the abundance and opacity of iron at the base of the convection zone (BCZ) at the boundary between the solar convection and radiative zones, and are the focus of the present study. Together, Fe xvii , Fe xviii and Fe xix contribute 85% of iron ion fractions 20%, 39% and 26% respectively, at the BCZ physical conditions of temperature T ∼ 2.11 × 106K and electron density Ne = 3.1 × 1022cc. We report heretofore the most extensive R-matrix atomic calculations for these ions for bound-bound and bound-free transitions, the two main processes of radiation absorption. We consider wavefunction expansions with 218 target or core ion ﬁne structure levels of Fe xviii for Fe xvii , 276 levels of Fe xix for Fe xviii , in the Breit-Pauli R-matrix (BPRM) approximation, and 180 LS terms (equivalent to 415 ﬁne structure levels) of Fe xx for Fe xix calculations. These large target expansions which includes core ion excitations to n=2,3,4 complexes enable accuracy and convergence of photoionization cross sections, as well as inclusion of high lying resonances. The resulting R-matrix datasets include 454 bound levels for Fe xvii , 1,174 levels for Fe xviii , and 1,626 for Fe xix up to n ≤ 10 and l=0 - 9. Corresponding datasets of oscillator strengths for photoabsorption are: 20,951 transitions for Fe xvii , 141,869 for Fe xviii , and 289,291 for Fe xix . Photoionization cross sections have obtained for all bound ﬁne structure levels of Fe xvii and Fe xviii , and for 900 bound LS states of Fe xix . Selected results demonstrating prominent characteristic features of photoionization are presented, particularly the strong Seaton PEC (photoexcitation-of-core) resonances formed via high-lying core excitations with ∆n = 1 that signiﬁcantly impact bound-free opacity.

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“…Clearly, equation (16) shows that determining U Ξ would require explicit determination of the electronic structure of every configuration within the SC, which would be an intractable problem when even a simple plasma might be described by thousands of SCs, each comprising thousands of unique configurations. In order to surmount this problem, we can approximate the one-electron energies of each configuration with their corresponding SC values.…”

Section: Partition Functionsmentioning

confidence: 99%

A superconfiguration calculation of opacity with consistent bound and continuum electron treatments using green’s functions

Gill¹,

Fontes²,

Starrett³

2023

J. Phys. B: At. Mol. Opt. Phys.

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One of the challenges in calculating the opacity of dense plasmas is the diﬃculty in consistently modeling electrons bound to nuclei and those that exist within the continuum of free states in electronic structure models. We address this issue by adapting the Green’s function approach, originally developed for use in average atom calculations, to the determination of superconﬁguration electronic structure. The spectra created using these superconﬁgurations indicate that a consistent treatment of continuum electronic structure is important for phenomena involving electrons near ionization thresholds, such as the pressure ionization of bound states and the opacity due to transitions near bound-free edges. Though important for dense plasmas, the detailed incorporation of continuum electrons into structure calculations does not have signiﬁcant impact on the recent discrepancies between the predicted and measured opacity of hot, dense iron [J. E. Bailey et al., Nature (London) 517, 56 (2015)]. We ﬁnd that the inclusion of plasma eﬀects through an ion-sphere model along with our treatment of continuum electronic states gives a description of pressure ionization in hot, dense aluminum that is in better agreement with experiment than methods that rely on perturbative descriptions of the plasma environment [D. J. Hoarty et al., Phys. Rev. Lett. 110, 265003 (2013)].

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Electron localization enhanced photon absorption for the missing opacity in solar interior

Cited by 10 publications

References 64 publications

The Strong Enhancement of Electron-Impact Ionization Processes in Dense Plasma by Transient Spatial Localization

The Strong Enhancement of Electron-Impact Ionization Processes in Dense Plasma by Transient Spatial Localization

R-Matrix calculations for opacities: II. Photoionization and oscillator strengths of iron ions Fe xvii, Fe xviii and Fe xix

A superconfiguration calculation of opacity with consistent bound and continuum electron treatments using green’s functions

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