The toroidal field, B_T(x, y), produced by vertical currents, J_z(x, y), derived from (a) the SHARP photospheric vector magnetogram and (b) the lower boundary data of the optimization solution for AR 11429 on 2012 March 6 23:36 UT. The background color map in each panel denotes J_z(x, y), the green contours denote PILs corresponding to B_z(x, y) = 0, and the dark green vectors denote B_T(x, y).