Visualizations of the magnetic field over NOAA AR 10930 before (top) and after (bottom) the X3.4 flare, shown against the corresponding map of ﹩B_{z}﹩. Sample field lines outline the field; white field lines close within the NLFF model volume, while colored field lines (purple or green for the two polarities of ﹩B_{z}﹩ at their base) leave that volume to connect to more distant regions. The rendered volumes (red) show where the electrical current densities are highest, using the same threshold level in both panels (cf. Fig. 2c). The low‐lying, compact current system below the large, high‐arching currents in the top panel corresponds to the site (position A in Fig. 2d) of the initial brightenings of the X3.4 flare and associated coronal mass ejection.