Simulations of F-UT patterns sorted by the polarity of the average IMF [B_Y]_GSEQ component during the prior hour. The top row shows the Russell-McPherron patterns P_RM(F, UT) in normalised power input into the magnetosphere simulated using the eccentric dipole geomagnetic field model for 2002 with (a) [B_Y]_GSEQ = +|B|, (b) [B_Y]_GSEQ = −|B|, and (c) an equal mix of [B_Y]_GSEQ = +|B| and [B_Y]_GSEQ= −|B|. The middle panels show the corresponding modelled patterns of P_m(F, UT) = P_RM(F, UT) · P_ψ(F, UT) · P_NS(UT). The observed patterns in aσ(midn) data shown in the bottom panels are for (g) [B_Y]_GSEQ < 0, (h) [B_Y]_GSEQ > 0 and (i) all data.