Left: SXT image of the X2.3 flare on 2000 November 24. The image is negative. The solid lines indicate L_x (shorter line) and L_y (longer line) measured by eyes. Middle: Light curves of the Al 12 filter images (solid line) and Be filter images (dotted line). Right: Temporal variation of thermal energy E_th. The solid line indicates the least‐squares fitting of the impulsive phase, which yields ﹩dE_{\mathrm{th}\,}/ dt=1.6\times 10^{28}﹩ ergs s⁻¹.