Transient space localization of electrons ejected from continuum atomic processes in hot dense plasma

Liu, Pengfei; Cheng, Guangquan; Hou, Yuxin; Zeng, Jiaolong; Yuan, Jianmin

doi:10.1038/s42005-018-0093-5

Cited by 38 publications

(15 citation statements)

References 46 publications

(50 reference statements)

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“…An accurate description of the plasma screening potential is of crucial importance for investigations of the atomic processes in dense plasmas (Liu et al 2018). Recent experimental investigations on electron-impact ionization show that the cross-sections and rates are enhanced by dense-plasma effects and cannot be explained by currently available atomic collision theory (Vinko et al 2015;van den Berg et al 2018).…”

Section: Resultsmentioning

confidence: 99%

Screening potential and continuum lowering in a dense plasma under solar-interior conditions

Zeng

Cheng

et al. 2020

A&A

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An accurate description of the screening potential induced by a hot, dense plasma is a fundamental problem in atomic physics and plasma physics, and it plays a pivotal role in the investigation of microscopic atomic processes and the determination of macroscopic physical properties, such as opacities and equations of state as well as nuclear fusion cross sections. Recent experimental studies show that currently available analytical models of plasma screening have difficulty in accurately describing the ionization-potential depression, which is directly determined by the screening potential. Here, we propose a consistent approach to determine the screening potential in dense plasmas under solar-interior conditions from the free-electron micro-space distribution. It is assumed that the screening potential for an ion embedded in a dense plasma is predominately determined by the free electrons in the plasma. The free-electron density is obtained by solving the ionization-equilibrium equation for an average-atom model to obtain the average degree of ionization of the plasma. The proposed model was validated by comparing the theoretically predicted ionization-potential depression of a solid-density Si plasma with recent experiments. Our approach was applied to investigate the screening potential and ionization-potential depression of Si plasmas under solar-interior conditions over a temperature range of 150–500 eV and an electron-density range of 5.88 × 1022–3.25 × 1024 cm−3. It can be easily incorporated into atomic-structure codes and used to investigate basic atomic processes, such as photoionization, electron-ion collisional excitation and ionization, and Auger decay, in a dense plasma.

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Section: Resultsmentioning

confidence: 99%

Screening potential and continuum lowering in a dense plasma under solar-interior conditions

Zeng

Cheng

et al. 2020

A&A

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“…For example, preliminary calculations of two-photon absorption [22] suggest that this neglected process would substantially increase the absorption. Another idea for missing physics was also recently published [54]. Refined calculations need to evaluate whether these suggested contributions are consistent with the entire Cr, Fe, and Ni data set.…”

Section: (C)] a 60-90%mentioning

confidence: 99%

Systematic Study of L -Shell Opacity at Stellar Interior Temperatures

et al. 2019

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The first systematic study of opacity dependence on atomic number at stellar interior temperatures is used to evaluate discrepancies between measured and modeled iron opacity [J. E. Bailey et al, Nature 517, 56 (2015)]. Hightemperature (>180 eV) chromium and nickel opacities are measured with 6-10% uncertainty, using the same methods employed in the previous iron experiments. The 10-20% experiment reproducibility demonstrates experiment reliability. The overall model-data disagreements are smaller than for iron. However, the systematic study reveals shortcomings in models for density effects, excited states, and open L-shell configurations. The 30-45% underestimate in the modeled short-wavelength quasi-continuum opacity was observed only from iron and only at temperature above 180 eV. Thus, either opacity theories are missing physics that has non-monotonic dependence on the number of bound electrons, or there is an experimental flaw unique to the iron measurement at temperatures above 180 eV.

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“…In such a treatment, the continuum electrons are completely coherent throughout the entire physical space during the process. In dense plasma, however, the continuum electrons collide randomly with the surrounding free electrons and ions, which results in a loss of phase of the electron matter wave and partial decoherence when the electron leaves the parent ion [ 24 ]. The partial decoherence of the continuum electrons is a natural many-body effect occurring in dense plasma and differs from plasma screening.…”

Section: Introductionmentioning

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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Transient space localization of electrons ejected from continuum atomic processes in hot dense plasma

Cited by 38 publications

References 46 publications

Screening potential and continuum lowering in a dense plasma under solar-interior conditions

Screening potential and continuum lowering in a dense plasma under solar-interior conditions

Systematic Study of L -Shell Opacity at Stellar Interior Temperatures

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

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