IMAGE - POLAR Concurrent Plasmapause Observations

M.L. Adrian, D.L. Gallagher, and P.D. Craven


Two critical issues that influence the quantitative scientific value of the
IMAGE Ultraviolet Camera (EUV) are: (1) the accuracy with which EUV imaging can
be used to determine the position/location of the plasmapause; and (2) the
sensitivity threshold of the EUV instrument. Previous studies have addressed
these issues via correlation of EUV-extracted plasmapause locations with steep
density gradient plasmapause encounters detected by the IMAGE Radio Plasma
Imager (PRI) pre-/post-EUV observation, employing the caveat of corotation.
Here, these issues are addressed through analysis of concurrent remote
observations of the plasmasphere/plasmapause made by IMAGE EUV with simultaneous
in-situ observations acquired by the Polar/TIDE/EFI instruments. Preliminary
results are presented with regards to the validity of the extraction of the
plasmapause using EUV and initial in-flight, in-situ estimates of the EUV
sensitivity threshold. Early estimates suggest a sensitivity threshold for EUV
of 25 pm 15 cm^(-3).

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Presentation, Fall A.G.U. Meeting, San Francisco, CA, 13-17 December 2004