CoMP and synthetic Doppler images. Panels (a)–(c) show the observational Doppler velocity by CoMP, at three time instances separated by a time interval of about 20 hr. The synthetic Doppler images of the prominence-cavity system at time = 18.24 hr, along the three LOSs (c), (b) and (a) in Figure 1 are displayed in panels (d)–(f), respectively, which correspond to CMER = −80°, −90°, −100° and BANG = 0°, 0°, 0° in forward modeling. We mark the reconnection and field-aligned flows with yellow and green arrows in panel (f).