The IMAGE spacecraft carries an extreme ultraviolet (EUV) imager
to detect solar EUV photons that are resonantly scattered by singly
ionized helium in the plasmasphere, the torus of cold dense plasma
surrounding the Earth in the inner magnetosphere. A
sophisticated computer deconvolution
technique is used to translate the EUV photon counts registered
by the instrument into images of the plasmasphere.
Because of the IMAGE spacecraft's
high apogee altitude (~7 Earth radii) and the EUV imager's wide
field of view, images generated from data acquired
at apogee show the structure of
the entire plasmasphere.
The combined analysis of the EUV images and RPI data on
plasmaspheric plasma density allows researchers to study the
structure and dynamics of the plasmasphere and plasmapause
as they change in response to
changing levels of magnetospheric activity, while correlated analyses
of EUV and NAI images yield insights into the nature of the
between the cold plasma of the plasmasphere and the hot plasmas of
ring current and the near-Earth plasma sheet.