The effects of radiative cascades on the x-ray diagnostic lines of Fe16+
TLDR
In this paper, the authors present complete collisional-radiative modelling results for the soft x-ray emission lines of Fe16+ in the 15 A-17 A range.Abstract:
We present complete collisional-radiative modelling results for the soft x-ray emission lines of Fe16+ in the 15 A–17 A range. These lines have been the subject of much controversy in the astrophysical and laboratory plasma community. Radiative transition rates are generated from fully relativistic atomic structure calculations. Electron-impact excitation cross sections are determined using a fully relativistic R-matrix method employing 139 coupled atomic levels through n = 5. We find that, in all cases, using a simple ratio of the collisional rate coefficient times a radiative branching factor is not sufficient to model the widely used diagnostic line ratios. One has to include the effects of collisional-radiative cascades in a population model to achieve accurate line ratios. Our line ratio results agree well with several previous calculations and reasonably well with tokamak experimental measurements, assuming a Maxwellian electron-energy distribution. Our modelling results for four EBIT line ratios, assuming a narrow Gaussian electron-energy distribution, are in generally poor agreement with all four NIST measurements but are in better agreement with the two LLNL measurements. These results suggest the need for an investigation of the theoretical polarization calculations that are required to interpret the EBIT line ratio measurements.read more
Citations
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Updated Atomic Data and Calculations for X-Ray Spectroscopy
TL;DR: AtomDB 2.0.2 as discussed by the authors is a database of atomic data and a plasma modeling code with a focus on X-ray astronomy, including new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions, including the iron L-shell ions from Fe+16 to Fe+23 and all of the hydrogen- and helium-like sequences.
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Chianti—an atomic database for emission lines. xii. version 7 of the database
TL;DR: The CHIANTI spectral code consists of an atomic database and a suite of computer programs to calculate the optically thin spectrum of astrophysical objects and carry out spectroscopic plasma diagnostics as discussed by the authors.
Journal ArticleDOI
Updated Atomic Data and Calculations for X-ray Spectroscopy
TL;DR: AtomDB 2.0.2 as mentioned in this paper is a database of atomic data and a plasma modeling code with a focus on X-ray astronomy, which includes several major updates to the fundamental atomic structure and process data held within AtomDB, incorporating new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions.
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Solar UV and X-ray spectral diagnostics
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Atomic data for x-ray astrophysics
TL;DR: The available atomic data used for interpreting and modeling x-ray observations can be divided into several levels of detail, ranging from compilations which can be used with direct inspection of raw data, such as line finding lists, to synthetic spectra which attempt to fit to an entire observed dataset simultaneously as mentioned in this paper.
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