Local transverse ion energization in and near the polar cusp

Ion conics are often observed in the dayside polar cusp region of the magnetosphere by the polar orbiting Viking satellite. These ion distributions may be locally heated perpendicularly to the ambient magnetic field to temperatures of about 100 eV. The conics are closely associated with increased electron fluxes but may occur equatorward of the region of ions injected from the magnetosheath. They are also closely related to waves with frequencies up to about 100 Hz. The wave electric field is directed mainly perpendicular to the ambient magnetic field and shows no clear structure near the ion gyrofrequencies or their harmonics. Observations of ion conics at 900 pitch angle and the related waves indicate that the waves may cause significant ion heating, especially of heavy ions. copyright American Geophysical Union 198