2020 Articles
Laboratory Calibration of Fe XII-XIV Line-Intensity Ratios for Electron Density Diagnostics
We have used an electron beam ion trap to measure electron-density-diagnostic line-intensity ratios for extreme ultraviolet lines from FeXII, XIII, and XIV at wavelengths of ≈185–205 and 255–276Å. These ratios can be used as density diagnostics for astrophysical spectra and are especially relevant to solar physics. We found that density diagnostics using the FeXIII 196.53/202.04 and the FeXIV 264.79/274.21 and 270.52A/274.21 line ratios are reliable using the atomic data calculated with the Flexible Atomic Code (FAC). On the other hand, we found a large discrepancy between the FAC theory and experiment for the commonly used FeXII (186.85 + 186.88)/ 195.12 line ratio. These FAC theory calculations give results similar to the data tabulated in CHIANTI, which are commonly used to analyze solar observations. Our results suggest that the discrepancies seen between solar coronal density measurements using the FeXII (186.85 + 186.88)/195.12 and FeXIII 196.54/202.04 line ratios are likely due to issues with the atomic calculations for FeXII.
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Arthanayaka et al. - 2020 - Laboratory Calibrations of Fe xii–xiv Line-intensi.pdf application/pdf 1 MB Download File
Also Published In
- Title
- The Astrophysical Journal
- DOI
- https://doi.org/10.3847/1538-4357/ab67b4
More About This Work
- Academic Units
- Astronomy and Astrophysics
- Published Here
- March 15, 2023