Year: 2004
Type: article
Abstract: R -matrix calculations of electron impact excitation rates in N-like S X are used to derive theoretical emission-line intensity ratios involving 2 s 2 2 p 3 -2 s 2 p 4 transitions in the 189-265 Å wavelength range. A comparison of these with observational data for solar flares and active regions, obtained with the Naval Research Laboratory's S082A spectrograph on board Skylab and the Solar EUV Rocket Telescope and Spectrograph, reveals that many of the S X lines in the spectra are badly blended with emission features from other species. However, the intensity ratios I (228.70 Å)/ I (264.24 Å) and I (228.70 Å)/ I (259.49 Å) are found to provide useful electron density diagnostics for flares, although the latter cannot be employed for active regions, because of blending of the 259.49 Å line with an unidentified transition in these solar features.
Source: The Astrophysical Journal
DOI: 10.1086/380305
Authors: F. P. Keenan, A. C. Katsiyannis, K. G. Widing
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funder: Leverhulme Trust
OpenAlex ID: W2081571282