Evolution of the flare. Panels (a), (c), (d), and (f) show the main evolution sequence in composite AIA 131 Å and 171 Å images. (b) The microflare and small ejection in the 304 Å difference image just before the arcade eruption. The HMI magnetogram contours at ±125 G are overlaid. The blue rectangle is used for the light curve in Figure 2(c). (e) The ribbon separation in 304 Å. The magenta circles in each image show the relevant footpoint locations. Cuts 1–3 are used for time slices in Figures 2(a)–(c), respectively. The two cyan boxes in panels (c) and (d) are for DEM analysis in Section 2.4.

(An animation of this figure is available.)

The video/animation of this figure is available in the online journal.