Dielectronic satellite spectra for highly charged helium-like ions - III. Calculations of n = 3 solar flare iron lines

New calculations have been carried out in a multiconfiguration intermediate coupling scheme for dielectronic satellite spectra in Fe XXIV of the type 1s²nl−1s 2p nl, for n = 2 and 3. These are for application to solar flare spectra. The n = 2 result is consistent with previous calculations. Satellites with n = 3 enable (a) features in the observed spectra to be identified and explained, (b) a correction to be made to the intensity of the Fe XXV resonance line, and (c) provide part of the data for an estimate of the contribution of satellites with $$n\geqslant3$$ to the overall dielectronic recombination process. The computed spectra are compared with the solar flare spectra of Grineva et al. (1973). The results are discussed in terms of plasma diagnostic techniques, and the further theoretical work required to complete our understanding of these spectra. This is important for the interpretation of future planned observations of solar flare iron lines in the soft X-ray region.