Magnetic structures associated with two jet-like activities. (a1)–(a3): vector magnetograms. The blue and red arrows denote the transverse magnetic field with positive and negative vertical magnetic fields, respectively. The yellow box in panel a1 shows the variation in the positive magnetic flux in the white box of panel a. (b1)–(b2) and (c1)–(c2): magnetic field lines derived by the NLFFF extrapolation at 06:00 UT. Panels b1, c1, and c2 are a top view, while panel b2 is a side view. An animation available online shows the evolution of vector magnetograms during the period from 04:00 UT to 07:48 UT.