PFSS model for CR 2157 (﹩{b}_{0}=1\times {10}^{-4}﹩), showing the large active region at longitude 250°. Panel (a) shows B_r on ﹩r={r}_{0}﹩ in grayscale (white positive, black negative), along with magnetic field lines colored by ﹩{ \mathcal A }| {B}_{r}| ﹩ (using the larger of the two endpoint ﹩| {B}_{r}| ﹩ values). Panel (b) shows ﹩{ \mathcal A }| {B}_{r}| ﹩ on ﹩r={r}_{0}﹩ in blue/red. In both cases the blue/red color scale is in units of ﹩{10}^{22}\,{\mathrm{Mx}}^{2}\,{\mathrm{cm}}^{-2};﹩ for clarity it is capped at ﹩\pm 5\times {10}^{22}﹩ in (b) but covers the full range in (a). The dashed black line in both panels shows the zero contour of B_r on ﹩r={r}_{0}﹩. The animation begins at CR 2098 and ends at CR 2226, with a realtime duration of 11 s. It places this active region into context as one of the larger active regions within the full solar cycle.

(An animation of this figure is available.)

The video/animation of this figure is available in the online journal.