First IBEX observations of the terrestrial plasma sheet and a possible disconnection event

Abstract

The Interstellar Boundary Explorer (IBEX) mission has recently provided the first all-sky maps of energetic neutral atoms (ENAs) emitted from the edge of the heliosphere as well as the first observations of ENAs from the Moon and from the magnetosheath stagnation region at the nose of the magnetosphere. This study provides the first IBEX images of the ENA emissions from the nightside magnetosphere and plasma sheet. We show images from two IBEX orbits: One that displays typical plasma sheet emissions, which correlate reasonably well with a model magnetic field, and a second that shows a significant intensification that may indicate a near-Earth (∼10 RE behind the Earth) disconnection event. IBEX observations from ∼0.5-6 keV indicate the simultaneous addition of both a hot (several keV) and colder (∼700 eV) component during the intensification; if IBEX directly observed magnetic reconnection in the magnetotail, the hot component may signify the plasma energization. Copyright 2011 by the American Geophysical Union.