Time evolution of the toroidal magnetic energy within the twisted upper-half magnetosphere for simulation G101Dn5In4n4m4 over the time interval ﹩0.525\,{{\rm{\Omega }}}_{{\rm{KH}}}^{-1}\leqslant t\leqslant 0.725\,{{\rm{\Omega }}}_{{\rm{KH}}}^{-1}﹩. The vertical dashed line marks the transition time separating the confined (left) and inflating (right) phases of the magnetosphere.