The Optically Thick Fe xvii Spectrum: X‐Ray, Extreme‐Ultraviolet, and Forbidden Line Ratios

Level populations, X-ray line fluxes, and extreme-ultraviolet (EUV) line intensities are calculated for a 37 level model of the Fe XVII ion, as functions of the column density of Fe XVII, in slab geometry and cylindrical geometry. The resonance lines at 15.02 and 15.25 Å are found to exhibit initial increases in fluxes relative to the forbidden line at 17.10 Å and the usual reference resonance line at 16.78 Å as optical thickness increases. Eleven EUV lines and the forbidden 2 p 5 3 s ( 3 P 0 - 3 P 1 ) transition near 1154 Å are also found to be relatively enhanced by opacity.