Oxygen energization by localized perpendicular electric fields at the cusp boundary
Waara, M.; Nilsson, H.; André, M.; Vaivads, A.; Lindstedt, T.; Khotyaintsev, Y. V.
Sweden
Abstract
We report Cluster observations of oxygen energization by several keV at the boundary between the high latitude cusp and lobe. A localized electric field at the cusp/lobe boundary is responsible for a significant part of the observed energization. Such electric fields can be related to the separatrix region of reconnection at the magnetopause. Ions are accelerated as they move non-adiabatically in the spatially inhomogeneous electric field. Additional heating may be provided by low frequency waves at the oxygen gyrofrequency.