RHESSI hard X-ray clean maps (dark contours) at 25–100 keV of spikes b) S1 and d) S2 and the pre-spike underlying components (a) and c)) on 2002 March 17 superposed on the longitudinal magnetogram taken at 19:46:01.11 UT by MDI. Each map is constructed with 2 s integration. The contour levels are 0.25, 0.4, 0.55, 0.7, and 0.85 of the maximum count rates of all the images, which is 0.57 photons cm^-2 s^-1 asec^-2. White contours indicate the polarity inversion line of longitudinal magnetic fields.