Comparison of low‐activity and net flare SW traces with density‐resolved synthetic spectra. The corresponding DVEM models are illustrated in the top panel, normalized to their peak values (low activity, thick solid line; flare, dashed line). In the bottom panels, note the logarithmic scale for the high signal‐to‐noise ratio low‐activity spectrum but linear scale for the weaker net flare spectrum. Observed spectra are shaded: the thick solid curves are the synthetic spectra for ﹩n_{e}=10^{10}﹩ cm⁻³; thin solid curves are for ﹩n_{e}=10^{11}﹩, 10¹², and 10¹³ cm⁻³. The observed and synthetic spectra were smoothed with a 0.4 Å FWHM Gaussian. Dot‐dashed curves depict ±1 σ photometric errors. Key density diagnostic lines are marked in the left‐hand panels, as in Fig. 2.