In the paper “Evolution of auroral asymmetries in the conjugate hemispheres during two substorms” by Østgaard et al. (Geophysical Research Letters, 38, L03101, doi:10.1029/2010GL046057, 2011), the geometry presented in Figure 3b is not correct. Instead, the geometry first suggested by Stenbaek-Nielsen and Otto  and shown here in Figure 1 should be used. For Interplanetary Magnetic Field (IMF) By < 0, Stenbaek-Nielsen and Otto  derived, according to Ampere's law, a north-to-south inter-hemispheric field aligned current (FAC) in the region of auroral arcs and a south-to-north FAC at the inner edge of the plasma sheet that maps to the region of region 2 currents (Figure 1). Applying this geometry to the case study presented by Østgaard et al.  would imply that a net FAC from the north to the south in the region of auroral arcs and the rest of the argument based on integrating the Faraday's law along a loop of two closed field is still valid.