Initial Results from the IMAGE Extreme Ultraviolet Imager

Bill R. Sandel, Robert A. King, W. T. Forrester,
Dennis L. Gallagher, A. Lyle Broadfoot, and C. C. Curtis

The Extreme Ultraviolet Imager (EUV) of the IMAGE mission is
providing the first global images of the He+ distribution in
Earth's plasmasphere. The EUV instrument images the He+
resonance line emission at 30.4 nm at a time resolution of
10 minutes and a spatial resolution of 0.1 Re. Each image
encompasses the entire plasmasphere in a single frame, to permit
study of the structure and dynamics of the plasmasphere in its
entirety. Here we survey several of the most striking features
of the plasmasphere as seen by EUV. These features include
convection tails, depleted regions that we call "voids,"
isolated magnetic flux tubes filled to higher He+ density than
their neighbors, and "shoulders" in the He+ distribution.

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Geophysical Research Letters, Vol. 28, No. 8, p. 1439, April 2001