Burch, J. L., IMAGE Overview, presented at the American Geophysical
Union Fall Meeting, San Francisco, December 15-19, 1996.

IMAGE Overview

J. L. Burch (Southwest Research Institute, San Antonio, TX 
78228-0510; ph.  1-210-522-2526; e-mail:  jburch@swri.edu)

The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) will
be NASAšs first MIDEX mission.  The overall objective of IMAGE is to
determine how the magnetosphere responds globally to the changing
conditions in the solar wind.  Specific questions to be addressed
include (1) What are the dominant mechanisms for injecting plasma into
the magnetosphere on substorm and magnetic storm time scales?  (2)
What is the directly driven response of the magnetosphere to solar
wind changes? and (3) How and where are magnetospheric plasmas
energized, transported, and subsequently lost during storms and
substorms?  The IMAGE mission will use four imaging techniques: 
neutral atom imaging (NAI) over an energy range from 10 eV to 200 keV,
far ultraviolet imaging (FUV) at 121 - 180 nm, extreme ultraviolet
imaging (EUV) at 30.4 nm, and radio plasma imaging (RPI).  NAI will be
used to image low-energy upward-flowing ionospheric ion populations,
the medium energy ions of the cusp and near-Earth plasma sheet, and
the energetic ions of the ring current.  The electron and proton
aurora and the hydrogen geocorona will be imaged in the FUV.  The
helium ion population of the plasmasphere will be imaged at EUV
wavelengths.  Finally, RPI will determine the locations of various
plasma density gradients and boundaries within the magnetosphere. 
This paper will describe the IMAGE science objectives,
instrumentation, spacecraft, and mission plan.