Examining Interhemispheric Properties of the Cusp

The magnetospheric cusp is a narrow region of geospace where the solar wind has direct access to the ionosphere and thermosphere. The low-altitude projection of the cusp is a site of concentrated energy dissipation, which leads to extraordinary thermospheric upwelling and prodigious outflows of ionospheric ions into the magnetosphere.  Although interhemispheric and seasonal differences in cusp morphology and properties are recognized, statistical empirical identifications and models do not properly capture important temporal and spatial features of the cusp.  We have analyzed cusp location, size and energization, and dynamics, using different identification methods applied to the Multiscale Atmosphere Geospace Environment (MAGE) global simulation model.  Interhemispheric differences are considered for a variety of seasonal and solar wind conditions.  Preliminary results indicate that under strong IMF By conditions, commonly used cusp identification methods do not agree and are associated with the direct-entry and Alfvenic cusps not being collated.  Furthermore, we find that the simulated cusp is not discernable in one hemisphere but is pronounced in the other hemisphere.  We explore under what conditions this occurs.