Atomic structure data based on average-atom model for opacity calculations in astrophysical plasmas

Trzhaskovskaya, M. B.; Nikulin, V. K.

doi:10.1016/j.hedp.2017.11.001

Cited by 5 publications

(7 citation statements)

References 28 publications

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“…Equation (16) involves that the bound wave functions are confined in the Wigner-Seitz cell, i.e. P nl (r) = 0 for r r WS [17][18][19] (see also reference [20], where this boundary condition is noted BC1). For the calculations of the wave functions of bound states, equation ( 6) is firstly integrated from the nucleus to r WS , and secondly, it is integrated in the backward direction.…”

Section: Description Of the Atomic Modelmentioning

confidence: 99%

Influence of plasma density on radiative recombination cross sections of oxygen ions

Ribière¹

2022

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

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Radiative recombination cross sections of oxygen ions from O+ to O6+ are calculated by an atomic model assuming central field and Hartree-Fock-Slater approximation for exchange potential. The recombining ions are considered on their ground states, to form recombined ions on their ground states as well as on several subshells up to 4d. The effect of plasma density on the cross sections is taken into account by varying the Wigner-Seitz cell representing the atomic volume containing bound and free electrons. It is shown that the increase of plasma density significantly enhances the cross sections involving excited states of the recombined ions at atmospheric pressures and beyond. These cross sections may be used in collisional-radiative models for fully ionized plasma simulations in the frame work of, for example, switches in Marx generator and laser-induced plasmas in air.

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Section: Description Of the Atomic Modelmentioning

confidence: 99%

Influence of plasma density on radiative recombination cross sections of oxygen ions

Ribière¹

2022

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

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“…) Here the superscript A means the quantity due only to the large component. For the relativistic case this means setting Q κ = 0 in the expressions for the density (8) and density of states (30), and in the Green's function (12) which is then used in expressions (11) and (32). For the non-relativistic case, there is no small component, so n e (r) = n A e (r) and χ( ) = χ A ( ).…”

Section: Equation Of Statementioning

confidence: 99%

“…The original presentation of the physical model used in Tartarus was given Liberman in references [3,4]. This particular model was then expanded on and explored in more detail by other authors, including references [5,6,7,8,9,10,11,12,13]. However, many other average atom like models with their own advantages and disadvantages were also developed.…”

Section: Introductionmentioning

confidence: 99%

Wide ranging equation of state with Tartarus: A hybrid Green’s function/orbital based average atom code

Starrett

Gill

Sjostrom

et al. 2019

Computer Physics Communications

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“…The average-atom model is used to evaluate the photoionization cross section σ bf (ω) for energies above the K-shell threshold (≈ 200 eV for boron) to 10 keV. It should be noted that average-atom models in various guises have been used previously to study photoionization and opacity in warm-and hot-dense plasmas [5][6][7][8][9][10][11][12][13][14][15]. The photoionization cross section calculated using the present model for a boron plasma at temperature T = 10 eV and density ρ = 2.463 g/cc, where the K-shell is filled, is in close agreement with the boron K-shell cross section given in the tabulation of Yeh and Lindau [1].…”

Section: Introductionmentioning

confidence: 99%

Opacity of shock-heated boron plasmas

Johnson

Nilsen

2019

High Energy Density Physics

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Standard measures of opacity, the imaginary part of the atomic scattering factor f 2 and the x-ray mass attenuation coefficient µ/ρ, are evaluated in shock-heated boron, boron carbide and boron nitride plasmas. The Hugoniot equation, relating the temperature T behind a shock wave to the compression ratio ρ/ρ 0 across the shock front, is used in connection with the plasma equation of state to determine the pressure p, effective plasma charge Z * and the K-shell occupation in terms of ρ/ρ 0 . Solutions of the Hugoniot equation (determined within the framework of the generalized Thomas-Fermi theory) reveal that the K-shell occupation in low-Z ions decreases rapidly from 2 to 0.1 as the temperature increases from 20eV to 500eV; a temperature range in which the shock compression ratio is near 4. The average-atom model (a quantum mechanical version of the generalized Thomas-Fermi theory) is used to determine K-shell and continuum wave functions and the photoionization cross section for x-rays in the energy range ω = 1 eV to 10 keV, where the opacity is dominated by the atomic photoionization process. For an uncompressed boron plasma at T = 10 eV, where the K-shell is filled, the average-atom cross section, the atomic scattering factor and the mass attenuation coefficient are all shown to agree closely with previous (cold matter) tabulations [1][2][3]. For shock-compressed plasmas, the dependence of µ/ρ on temperature can be approximated by scaling previously tabulated cold-matter values by the relative K-shell occupation; however, there is a relatively small residual dependence arising from the photoionization cross section. Attenuation coefficients µ for a 9 keV x-ray are given as functions of T along the Hugoniot for B, C, B 4 C and BN plasmas.

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Atomic structure data based on average-atom model for opacity calculations in astrophysical plasmas

Cited by 5 publications

References 28 publications

Influence of plasma density on radiative recombination cross sections of oxygen ions

Influence of plasma density on radiative recombination cross sections of oxygen ions

Wide ranging equation of state with Tartarus: A hybrid Green’s function/orbital based average atom code

Opacity of shock-heated boron plasmas

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