Fe vii Emission Lines in the Wavelength Range 193–197 Å

• Published in: The Astrophysical journal Vol. 908; no. 1; pp. 104 - 111
• Main Authors: Young, Peter R., Ryabtsev, Alexander N., Landi, Enrico
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.02.2021; IOP Publishing
• Subjects: Astrophysics; Atomic spectroscopy; Coronal loops; Emission; Emission lines; Fine structure; Imaging spectrometers; Line intensities; Solar extreme ultraviolet emission; Solar spectra; Solar transition region; Spacecraft; Spectroscopy; Wavelengths
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/abd39b

Abstract The identifications of Fe vii emission lines in the wavelength range 193–197 Å are discussed in the light of new measurements of laboratory spectra and atomic data calculations. This region is of importance to studies of solar spectra from the EUV Imaging Spectrometer (EIS) on board the Hinode spacecraft, which has its peak sensitivity at these wavelengths. Ten lines are measured, arising from seven fine structure levels in the 3 p 5 3 d 3 configuration. Two lines have not previously been reported and lead to new experimental energies for the levels. Updated experimental energies are obtained for the remaining levels. The new atomic model is used to compute theoretical values for the two density diagnostic ratios λ 196.21/ λ 195.39 and λ 196.21/ λ 196.06, and densities are derived from EIS spectra of coronal loop footpoints.