Auroral proton precipitation into the high-latitude cusp spots in the northward IMF simulation. (a) Differential number flux of proton precipitation in the northern cusp spot, with the mean precipitating energy indicated with a black line. (b) Integral energy flux of proton precipitation in the northern cusp spot. (c) Same as (a) for the southern cusp spot. (d) Same as (b) for the southern cusp spot. The time intervals shaded in grey indicate that the corresponding virtual spacecraft was not magnetically connected to the inner boundary of the simulation.