Figure 4 shows the field-aligned current patterns at the northern ionosphere for these two runs, with Figure 4a again showing the low-density case and Figure 4b the high-density case. In these plots, red color indicates northward (downward) current and blue indicates southward (upward) current. The currents are larger in the high-density case since more Alfvén wave power is transmitted through the torus. Since upward current is generally associated with auroral emissions, the blue spots are a proxy for the aurora in this figure (although it should be acknowledged that even downward current can be associated with counterstreaming fluxes that can produce aurora, as noted by Mauk et al., 2020). The current in the main Alfvén wing is the most intense current with the reflected wing (at 75° longitude) being the next most intense; however, there are weaker currents associated with the secondary reflections as well. (Note that the resolution of the simulation in the longitudinal direction is 0.1°, so that the small fluctuations are well resolved.)