New Identifications of Si viii and S x Lines in the Solar Coronal Spectrum Measured bySOHO/SUMER

This paper reports the identification of 14 lines in the solar coronal spectrum as high-excitation 2 s 2 2 p 2 3 s -2 s 2 2 p 2 3 p and 2 s 2 2 p 2 3 p -2 s 2 2 p 2 3 d transitions in Si VIII and S X (N I isoelectronic sequence). The analysis combines solar spectra, recorded by the SUMER (Solar Ultraviolet Measurement of Emitted Radiation) instrument on board the Solar and Heliospheric Observatory ( SOHO ) satellite, with laboratory data obtained with the beam-foil technique. Theoretical gA values and branching ratios for the observed lines, based on semiempirical calculations, are also presented. Intensity ratios between the newly identified high-excitation transitions and known forbidden transitions within the 2 s 2 2 p 3 ground configuration can be used in determining coronal plasma temperatures in the 70-120 eV range.