3D magnetic configuration and current sheet at 03:52 UT in the MHD model. (a) Distribution of J/B in a representative y–z slice; the green box highlights the reconnection current sheet. (b) Representative magnetic field lines overlaid on the bottom B_z map, illustrating conjugate connectivity linking positive-polarity footpoints P1 and P2 to the negative-polarity footpoint N; the black arrow points to the X-type geometry at the reconnection site. (c) Extracted 3D current sheet structure colored by J, showing stronger current density toward lower heights.