Supplementary Material Figure 1: Characteristics of the AE index and IMF for the 15 November-15 December 2016 period. Panel (a) shows the time series of the Auroral Electrojet (AE) index (b) IMF Bx, (c) IMF By, (d) IMF Bz, all from OMNIWeb, with the times of Swarm events included in the analysis being marked on (b), (c) and (d) with blue circles for the corresponding IMF orientations. (e) shows the Poynting fluxes for dayside events (marked with circles) for the northern and southern hemispheres (blue and red, respectively); dashed lines represent linear connections between individual events. Conjugate events in the statistical event datasets, defined as those which occurred on conjugate hemispheres within 30 minutes of each other, are marked with crosses. These conjugate events are isolated and plotted in figure (g). Panels (f) and (h) repeat figures (e) and (g) for the nightside. In panels (e) to (h) the AE Index from (a) is plotted in the background in light gray to give context to the variability of Poynting fluxes in response to varying solar wind and geomagnetic driving conditions.