Fig. 8

Example of flare variations. Flare variations for the C8.8 flare on 2010 May 5 as adapted from Woods et al. (2011). The relative irradiance (Rel. Irr.), being the solar irradiance spectrum minus the pre-flare spectrum, represents well the flare variations over its different phases. The transition region He II 30.4 nm emission highlights the impulsive phase. The GOES X-ray (0.1–0.8 nm) defines the gradual phase, and the hot corona Fe XX / Fe XXIII 13.3 nm emission behaves almost identically as the X-ray. The cool corona Fe IX 17.1 nm emission is the EUV emission with the largest amount of coronal dimming that often follows after the impulsive phase. The warm corona Fe XVI 33.5 nm emission has its first peak a few minutes after the X-ray gradual phase peak and then has a second peak many minutes later. The change in slope of the GOES X-ray during the gradual phase is indicative of the late phase contribution (second Fe XVI peak). The four vertical dashed lines, left to right, are for spectra in Figure 9 of the pre-flare, main phase, coronal dimming, and EUV late phase