Paper#: 110
Poster #:
Session Name: Workshop 3A: M/I Coupling
Room: West Ballroom
Day: Tuesday
Time: 2:40-3:00 p.m.
Abstract Title: Simultaneous Observations of Precipitating and Trapped Particle Substorm Signatures Using IMAGE ENA Tracking and FUV Proton Aurora Observations.
PresentSurname: Jahn, J.-M.
All Authors: J.-M. Jahn, D. J. McComas, C. J. Pollock, P.C. son Brandt, R. Demajistre, D. G. Mitchell, E. C. Roelof, M..G. Henderson, G..D. Reeves, R. Skoug, M.F. Thomsen , H. U. Frey, S. B. Mende
Abstract : With global ENA imaging available on a more routine basis, we have available a powerful tool to observe the spatial distribution of plasma in the inner magnetosphere. We have been developing methods to quantify large-scale particle motions using global energetic neutral atom (ENA) imaging from the IMAGE MENA and HENA detectors. Specifically, we explore the level of analysis possible prior to subjecting ENA measurements to image inversion techniques. We are presenting tracking results from several substorm events in 2000 and 2001. Events were chosen such that IMAGE was located reasonably close to the magnetic pole, providing a good view of the inner magnetosphere while minimizing adverse viewing effects. We track the earthward movement of plasma during the substorm expansion phase and the local time extent of medium energy plasma (which is subject to the competition between convection, corotation, and magnetic drifts) as well as the gradient curvature drift of high energy plasma (10's of keV and up). We compare the spatio-temporal development of ENA substorm measurements to simultaneous proton aurora measurements from the IMAGE FUV instrument. In general, the local time distribution of proton aurora and ENA observations corresponds well. The temporal correlation between those techniques is not as good, often showing a slower rise and decay of ENA emissions when compared to the proton aurora. We also discuss potential ramifications of using direct ENA tracking and proton aurora observations as opposed to comparing plasma populations inverted from ENA observations with proton aurora measurements mapped to the equatorial plane.