The RHESSI (10–20 keV) and LC-MSDP-SECIS Hα light curves of the K9 flaring kernel during the B2.5 flare on 2004 May 3. The Hα light curves are shown for line centre and  ± 0.6 Å from the line centre. The data in the upper panel were smoothed using a 4-s box-car filter for the RHESSI light curve and a 1-s box-car filter for the Hα light curves. The RHESSI light curves in the bottom panel were smoothed using a 0.5-s box-car filter (thin curves) and a 4-s box-car filter (thick curves), while the Hα light curves shown are unsmoothed (thin curves) and smoothed using a 1-s box-car filter (thick curves). The vertical grey strips (labelled a–c) are shown magnified in the bottom panel. The error bars indicate the standard deviations calculated for Hα and X-ray light curves. The Hα and RHESSI HXR energy flux ranges are defined in Table 2.