Mean energy maps obtained using the CR(E, θ) relationship modeled for the case of an initial monoenergetic electron flux distribution, and using the CR observed during PJ11 (see Fig. 4) in the north (left panel) and south (right panel) auroral regions. The iso-energy lines have values of 1 keV, 5 keV, and 10 keV, are in steps of 20 keV between 10 keV and 300 keV, and are then in steps of 100 keV between 300 and 900 keV.