To interpret this figure, note that Io’s diameter of 3644 km corresponds to 0.051 RJ and 0.49° of longitude. Using a dipole mapping, this corresponds to a footprint of about 140 km (0.11°) in latitude and 260 km in longitude. At a speed of 57 km/s, Io moves about one diameter in a minute. The field-aligned current at Io is generated at the Jupiter-facing edge and the edge on the far side from Jupiter (e.g., Saur et al., 2004), producing the U-shaped pattern seen in the figures. The current pattern oscillates back and forth with an amplitude of about 0.03 in L shell, which corresponds to a distance of 80 km, close to the 100 km transverse displacement seen by Mura et al. (2018). This pattern is apparently repeated about every 0.3° in the low-density model and 0.5° in the high-density model, implying a time scale for reflection of about 1 minute. Although Mura et al. (2018) state that specular reflection does not give this time scale for reflections off the torus, our full wave calculation suggests that reflections do return to the ionosphere on this time scale.