Comparing the latitudinal distribution of the Pc1 intensity and the position of subauroral proton spots

The latitudinal position of subauroral proton spots (special proton auroras observed from the IMAGE satellite) has been compared with the Pc1 pulsation intensity distribution determined using the data from the Finnish meridional network of induction magnetometers. It has been indicated that a Pc1 intensity maximum is always observed at the station that is closer to the proton aurora projection. Two Pc1 bands were registered in the event when two proton auroral spots were simultaneously observed at different latitudes. In this case, the Pc1 intensity distribution maximum at lower frequencies was related to a proton auroral spot at a higher latitude and vice versa. Such a spatial correlation between Pc1 pulsations and proton auroral spots, together with the previously established time correlation between these phenomena, demonstrates that subauroral proton spots reflect the region of ion cyclotron instability in the equatorial magnetosphere at the level of the ionosphere.