Top panel: toroidal field amplitude, at r = 0.706  R_⊙ and at θ = 14° north (solid, black) and south (dashed, red). The dashed line represents the buoyancy threshold (). The corresponding analog to a butterfly diagram is presented below for the field at the same depth. Blue represents negative fields, red positive fields, and green an average of zero. The contours enclose the areas where eruptions occur (B_φ > B_c).