Theoretical ratios for the EUV lines of A1 VIII ions

Theoretical line ratios for the A1viii ion have been investigated using an atomic model including the first fifteen energy levels, and taking account of various physical processes. The line emissivities as a function of electron density have been computed. Density-dependent theoretical line ratios are presented and their diagnostic applications in the solar atmosphere are discussed with the help of theoretical line intensities computed using an atmospheric model for the quiet Sun.