For low-density plasmas, the ionization balance can be properly described by the normal Saha equation in the chemical picture. For dense plasmas, however, nonideal effects due to the interactions ...between the electrons and ions and among the electrons themselves affect the ionization potential depression and the ionization balance. With the increasing of plasma density, the pressure ionization starts to play a more obvious role and competes with the thermal ionization. Based on a local-density temperature-dependent ion-sphere model, we develop a unified and self-consistent theoretical formalism to simultaneously investigate the ionization potential depression, the ionization balance, and the charge states distributions of the dense plasmas. In this work, we choose Al and Au plasmas as examples as Al is a prototype light element and Au is an important heavy element in many research fields such as in the inertial confinement fusion. The nonideal effect of the free electrons in the plasmas is considered by the single-electron effective potential contributed by both the bound electrons of different charge states and the free electrons in the plasmas. For the Al plasmas, we can reconcile the results of two experiments on measuring the ionization potential depression, in which one experiment can be better explained by the Stewart-Pyatt model while the other fits better with the Ecker-Kröll model. For dense Au plasmas, the results show that the double peak structure of the charge state distribution appears to be a common phenomenon. In particular, the calculated ionization balance shows that the two- and three-peak structures can appear simultaneously for denser Au plasmas above ∼30g/cm^{3}.
The thermodynamic as well as optical properties of strongly coupled plasmas depend crucially on the average degree of ionization and the ionic state composition, which, however, cannot be determined ...by using the normal Saha equation usually used for the ideal plasmas. Hence, an adequate treatment of the ionization balance and the charge state distribution of strongly coupled plasmas is still a challenge for theory due to the interactions between the electrons and ions and among the electrons themselves. Based on a local density temperature-dependent ion-sphere model, the Saha equation approach is extended to the regime of strongly coupled plasmas by taking into account the free-electron-ion interaction, the free-free-electron interaction, the nonuniform free-electron space distribution, and the free-electron quantum partial degeneracy. All the quantities, including the bound orbitals with ionization potential depression, free-electron distribution, and bound and free-electron partition function contributions, are calculated self-consistently in the theoretical formalism. This study shows that the ionization equilibrium is evidently modified by considering the above nonideal characteristics of the free electrons. Our theoretical formalism is validated by the explanation of a recent experimental measurement of the opacity of dense hydrocarbon.
•Auger decay processes of the hollow states K−2V of Ne+ were theoretically studied.•Direct double Auger decay rates were investigated and account for ∼5%.•Natural lifetime widths including DDAD ...processes agree better with experiment.•Theoretical results successfully interpreted the measured Auger spectra.
In this study, we theoretically investigated single and double Auger decay processes from the K−2V (V = 3s, 3p, 3d, 4s, 4p, 4d) hollow states of Ne+ in the framework of the first- and second-order perturbation theory implemented by the distorted wave approximation. The direct double Auger decay rates were calculated based on the separation of knock-out and shake-off mechanisms. Atomic data, including the transition energy, single and double Auger decay rates and natural lifetime width, are obtained and compared with the experimental and theoretical results available in the literature. The natural lifetime widths of the K−2V hollow states, including the contributions from single and direct double Auger decay, are in excellent agreement with a recent experiment. Using our theoretical results, we diagnosed the relative population fractions of the initial quantum states prepared in the experiment and interpreted the measured Auger spectra. There is an excellent agreement between the theoretical and experimental results. Finally, the hypersatellite Kα radiative transitions relevant to these hollow states were investigated using the natural lifetime widths determined by single and direct double Auger rates.
Extremely exotic dense matter states can be produced in the interaction of a relativistic femtosecond optical laser with a solid density matter. Here we theoretically investigate triple-core-hole ...(TCH) states produced by an intense polychromatic x-ray field formed by hot electrons in the interaction of a relativistic femtosecond optical laser with a thin silver foil. X-ray emission spectra of solid-density silver plasmas show unambiguously the production of TCH states at an electron temperature of a few hundreds of eV and radiative temperature of 1-3 keV of the polychromatic x-ray field. Practical calculations show that the emissivity originating from the TCH states exceeds that from the single- and double-core-hole states in Ne-like Ag
at electron temperature of ~500 eV and radiative temperature of ~1500 eV. For the neighbouring ionization stages of Ag
and Ag
, TCH emissivity is roughly equivalent or comparable to that from the single- and double-core-hole states. Present work deepens our insight into investigation of the properties of extremely exotic states, which is important in high energy density physics, astrophysics and laser physics.
The energy levels, oscillator strengths, and electron impact collision strengths are calculated for the Xe{sup 10+} ion using the configuration interaction scheme implemented by the Flexible Atomic ...Code. These data pertain to the 3917 levels belonging to the following configurations: 4s{sup 2}4p{sup 6}4d{sup 8}, 4s{sup 2}4p{sup 6}4d{sup 7}4f, 4s{sup 2}4p{sup 6}4d{sup 7}5l (l = s, p, d, or f), 4s{sup 2}4p{sup 5}4d{sup 9}, 4s{sup 2}4p{sup 5}4d{sup 8}4f, 4s{sup 2}4p{sup 5}4d{sup 8}5l, 4s{sup 2}4p{sup 6}4d{sup 6}5s5p, 4s{sup 2}4p{sup 6}4d{sup 6}5p5d. Configuration interactions among these configurations are included in the calculation. Collision strengths are obtained at 10 scattered electron energies (1-1000 eV) and are tabulated here at five representative energies of 10, 50, 100, 500, and 1000 eV. Effective collision strengths are obtained by assuming a Maxwellian electron velocity distribution at 10 temperatures ranging from 10 to 100 eV, and are tabulated at five representative temperatures of 10, 30, 50, 70 and 100 eV in this work. The whole data set should be useful for research involving extreme ultraviolet emission from Xe{sup 10+}.
Radiative opacity and emissivity of tin plasmas at average ionization degree of about 10 was investigated in detail by using a fully relativistic detailed level accounting approach, in which main ...physical effects on the opacity were carefully taken into account. Among these physical effects, configuration interaction, in particular core-valence electron correlations, plays an important role on the determination of accurate atomic data required in the calculation of opacity. It results in a strong narrowing of lines from all transition arrays and strong absorption is located in a narrow wavelength region of 12.5-14 nm for Sn plasmas. Using a complete accurate atomic data, we investigated the opacity of Sn plasmas at a variety of physical condition. Among the respective ions of Xe6+-Xe15+ , Xe10+ has the largest absorption cross section at 13.5 nm, while the favorable physical condition for maximal absorption at 13.5 nm do not mean that Xe10+ has the largest fraction. Comparison with other theoretical results showed that a complete set of consistent accurate atomic data, which lacks very much, is essential to predict accurate opacity. Our atomic model is useful and can be applied to interpret opacity experiments. Further benchmark experiments are urgently needed to clarify the physical effects on the opacity of Sn plasmas.
Energy levels, oscillator strengths, and electron impact collision strengths have been calculated for Ge-, Ga-, Zn-, Cu-, Ni-, and Co-like Au ions. For Ni-like Au, these atomic data are obtained ...among the levels belonging to the configurations of (Ne)3s
23p
63d
10, 3s
23p
63d
9
nl, 3s
23p
53d
10
nl, and 3s 3p
63d
10
nl (
n
=
4, 5;
l
=
0,
1,
…
,
n
−
1). For other Au ions, more levels have been obtained with special attention to atomic data up to transitions of 5f
→
3d for emission or 3d
→
5f for absorption. Configuration interactions are taken into account for all levels included. Collision strengths have been obtained at 20 scattered electron energies (5–40,000
eV) and they are listed at six representative energies of 100, 500, 1000, 5000, 10,000, and 20,000
eV in this work. Effective collision strengths have been obtained by assuming a Maxwellian electron velocity distribution at 10 representative temperatures ranging from 500 to 5000
eV. The present dataset should be adequate for most applications. The energy levels are expected to be accurate to within 0.5%, while oscillator strengths and collision strengths for strong transitions are probably accurate to better than 20%. The complete dataset is available electronically from
http://www.astronomy.csdb.cn/EIE/.
PDF
