Time sequence images with a small FOV of about 24 Mm × 24 Mm in HRI_EUV (top 12 panels) and HRI_Lyα (middle 12 panels) passbands, and running difference images (bottom 12 panels) in the HRI_EUV passband. The green contours represent the HRI_EUV emission at the level of 1000 DN s⁻¹. Two cyan curves mark the curved slits along the UBP, and the green symbol of ‘*’ indicate the zero of y-axis in Fig. 3. The magenta arrows outline moving structures.