AI ix emission line ratios in solar flares observed with the S082A spectrograph on board Skylab

Abstract

Theoretical electron-density-sensitive emission line ratios in B-like AI ix are presented for R =I(385.01 Å)/I(392.42 Å). A comparison of these with high spectral resolution solar flare data, obtained with the S082A slitless spectrograph on board Skylab, reveals agreement between theory and observation for those spectra that were observed during the later stages of the flares. These results provide experimental support for the accuracy of the line-ratio calculations, and also resolves discrepancies found previously when the theoretical results were compared with solar observations from the S-055 instrument on board Skylab. However, the agreement between theory and observation for a spectrum obtained during the early stages of a flare is very poor, which probably indicates that the 392.42 Å line is blended with a transition arising from a species formed at a very high electron temperature. © 1994 Kluwer Academic Publishers.