87th AMS Annual Meeting

Tuesday, 16 January 2007: 8:45 AM
Global measurement of the energetic ion precipitation from the storm time ring current using ENAs
210A (Henry B. Gonzalez Convention Center)
Craig J. Pollock, Southwest Research Institute, San Antonio, TX; and J. M. Jahn and A. Isaksson
Energetic ion precipitation represents a major ring current loss mechanism and a substantial source of atmospheric heating and ionization. While not dominant on a global scale, ring current ion precipitation can regionally dominate the thermospheric energy budget and can also determine regional night side ionospheric conductance profiles, particularly at sub-auroral latitudes. Heating and ionization due to energetic ion precipitation from the ring current can be particularly intense during the main phase of the geomagnetic storm, when the isotropic component of ring current ions are continually refreshed by ongoing injection from the geomagnetic tail. We will present remote observations of energetic ion precipitation during the main phase of the great 2003 Halloween geomagnetic storm, using the Medium Energy Neutral Atom (MENA) imager on board the IMAGE spacecraft. These observations demonstrate the ability of an appropriately placed ENA imager to quantify the global energy dependent ion precipitation from the ring current and, therefore, provide an assessment of the energy input and ionization production associated with this important storm-time process.

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