An Approach Towards Contour Generation Using Structural Operators for Use in GIS Based Applications

Pradhan, Ashis; Pradhan, Mohan P.; Pradhan, Ratika

doi:10.2139/ssrn.4370099

Cited by 1 publication

(7 citation statements)

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“…Recently, with several improvements in the extended Rmatrix and opacity codes large-scale data have been computed for Fe ions Fe xvii , Fe xviii and Fe xix , which determine over 80% of iron opacity near BCZ conditions (Pradhan et al (2023); Nahar et al (2023); Pradhan (2023); Zhao et al (2023). The R-matrix (RM) framework and comparison with existing opacity models based on atomic structure codes and the distorted wave (DW) approximation, and associated physical effects, are described in detail.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

“…Plasma broadening effects are very important, but manifest themselves quite differently in the two methods. Resonances in RM photoionization cross sections are broadened far more than lines as function of temperature and density since autoionization widths, shapes and heights are considered explicitly (Pradhan (2023). Also, the intrinsically asymmetric features of the large Seaton photoexcitation-of-core (PEC) resonances in bound-free cross sections are preserved in RM calculations.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

“…In order to study the behavior of MHD and QMHD, we employ the new RMOP opacity codes (Pradhan et al (2023), varying the number of atomic levels for each Fe ion, and both sets of EOS parameters at specified temperaturedensity pairs for a particular ion. Monochromatic opacities are computed at the same frequency mesh in the variable and range 0 u = hν/kT 20, as in OP work (Seaton et al (1994); Mendoza et al (2007).…”

Section: Opacity Computationsmentioning

confidence: 99%

“…Opacity computations depend on atomic data on the one hand and the plasma EOS on the other (The Opacity Project Team (1995); Seaton et al (1994); Pradhan et al (2023). Voluminous amounts of data are needed for all photon absorption and scattering processes in order to ensure completeness.…”

Section: Introductionmentioning

confidence: 99%

“…Voluminous amounts of data are needed for all photon absorption and scattering processes in order to ensure completeness. Recently, accurate and extensive calculations of atomic data for iron ions of importance under BCZ conditions have been carried out using the R-matrix method (Pradhan et al (2023); Nahar et al (2023); Pradhan (2023); Zhao et al (2023). However, the EOS determines how and to what extent the atomic data contribute to monochromatic and mean opacities at a given temperature and density.…”

Section: Introductionmentioning

confidence: 99%

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Interface of equation of state, atomic data, and opacities in the solar problem

Pradhan

2023

Monthly Notices of the Royal Astronomical Society: Letters

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The dependence of the Rosseland Mean Opacity (RMO) on the equation-of-state and the number of included atomic levels of iron ions prevalent at the solar radiative/convection boundary is investigated. The ”chemical picture” Mihalas-Hummer-Däppen MHD-EOS, and its variant QMHD-EOS, are studied at two representative temperature-density sets at the base of the convection zone (BCZ) and the Sandia Z experiment: (2 × 106K, 1023/cc) and (2.11 × 106K, 3.16 × 1022/cc), respectively. It is found that whereas the new atomic datasets from accurate R-matrix calculations for opacities (RMOP) are vastly overcomplete, involving hundreds to over a thousand levels of each of the three Fe ions considered — Fe xvii , Fe xviii , Fe xix — the EOS constrains contributions to RMOs by relatively fewer levels. The RMOP iron opacity spectrum is quite different from the Opacity Project distorted wave model and shows considerably more plasma broadening effects. This work points to possible improvements needed in the EOS for opacities in high-energy-density (HED) plasma sources.

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