Inner-shell transitions of Fe XXIII and Fe XXIV in the X-ray spectra of solar flares

New calculations for the dielectronically excited n=2p FeXXIV and n=2l, 3l, 4l, 5l and 6p FeXXIII satellites are presented and compared with solar-flare spectra obtained with the Bent Crystal Spectrometer instrument on board the Solar Maximum Mission spacecraft. Excellent overall agreement is achieved between the calculated and observed spectra. The calculations show that high-n satellites in FeXXIII tend to converge in wavelength on the FeXXIV transitions of the type 1s22s-1s2s2p. For example, the diagnostically important line q, which in the past has been used as an indicator of the lithium- to helium-like ion balance N(FeXXIV)/N(FeXXV), is shown to have a contribution from the FeXXIII satellites amounting to about 10% of its total. Three different ionization balance calculations are considered (Jacobs et al., 1977; Shull and van Steenberg, 1982; Doyle and Raymond, 1981). Implications for the use of the FeXXIII-XXV spectrum as a diagnostic of solar flares are discussed. (orig.)