Dielectronic satellite spectra for highly charged helium-like ions - V. Effect of total satellite contribution on the solar flare iron spectra

Abstract

For satellites of the type 1s² nl–1s 2pnl in Fe XXIV, wavelengths and intensities have been calculated for n = 4. Together with previous calculations for n = 2 and 3, these enable the wavelengths and decay rates to be scaled for higher values of n. The series up to n = 11 for satellites of the resonance line $${1s}^{2}-{1s}\,{2p} \,^{1}{P}_{1}$$, and up to n = 16 for satellites of the inter-combination line $${1s}^{2}-{1s}\,{2p} \,^{3}{P}_{1}$$, have been derived. This leads to a good estimate for the contribution of satellites to the apparent wavelength shift, width, and intensity of the resonance line, and thus to a value of the correction factor α needed for deriving electron temperature from satellite/ resonance line ratios, as described in Papers I and II in this series. Also obtained, from the sum of all the satellites, is a new value for the major contribution (~ 90 per cent) to the total dielectronic recombination rate. At typical flare temperatures of $${20\times 10}^{6}$$ K, this is greater by a factor of two than values obtained from earlier semi-empirical formulae.