Sources of plasma in the high altitude cusp

► Cusp identification methods are inconsistent. ► Ionospheric investigators do not include boundary layer plasmas in the cusp. ► Magnetospheric investigators include boundary layer plasmas in the cusp. ► Boundary layer plasmas often include O+ and He+ with 100 keV energies. ► There is no need for a new acceleration mechanism to explain 100 keV ionospheric ions in the high altitude cusp.