Photon scattering in the solar ultraviolet lines of HeI and HeII by Jordan, C, Smith, G, Houdebine, E

“…Observations made with the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO) are used to investigate the behaviour of the intensities of the emission lines of He I, He II and O III at the quiet Sun-centre and at θ = 60° towards the equatorial limb. …”

The anomalous intensities of helium lines in a coronal hole by Jordan, C, Macpherson, K, Smith, G

“…Observations made at the quiet Sun-centre with the Coronal Diagnostic Spectrometer (CDS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instruments on the Solar and Heliospheric Observatory (SOHO) have shown that the intensities of the resonance lines of He I and He II are significantly larger than predicted by emission measure distributions found from other transition region lines. …”