Measurement and Modeling of Density‐Sensitive Lines of Fe xiii in the Extreme Ultraviolet

Abstract

We present an analysis of the spectral emission of Fe xIII near 200 Å. High-resolution spectra were recorded at two densities (̃2 x 1011 and ̃ 1013 cm-3) in the laboratory and compared to collisional radiative model calculations based on the CHIANTI database, and to models using atomic data from distorted-wave and R-matrix calculations. The Fe xIII lines in this wavelength range are sensitive indicators of plasma density below ̃ 1011 cm -3. The laboratory data thus test calculations in the astrophysical high-density limit. Significant differences between the measurements and models were found for several line ratios. Differences in the wavelengths employed in the different models also changed the agreement with the measurements. The best agreement was found for comparisons with CHIANTI. © 2008. The American Astronomical Society. All rights reserved.