Automated Detection of the Magnetopause for Space Weather from the 
IMAGE Satellite

Michael L. Rilee (a) and James L. Green (b)

a - Raytheon Information Technology & Scientific Services
b - NASA Goddard Space Flight Center

Abstract

The Radio Plasma Imager (RPI) is a low power radar on board the IMAGE
spacecraft to be launched early in year 2000. The principal science
objective of RPI is to characterize the plasma in the Earth's
magnetosphere by radio frequency imaging. A key product of RPI is the
plasmagram, a map of radio signal strength vs. echo delay-time vs.
frequency, on which magnetospheric structures appear as curves of
varying intensity. Noise and other emissions will also appear on RPI
plasmagrams and when strong enough will obscure the radar echoes. RPI
echoes from the Earth's magnetopause will be of particular importance
since the magnetopause is the first region that the solar wind impacts
before producing geomagnetic storms. To aid in the analysis of RPI
plasmagrams and find all echoes from the Earth's magnetopause, a
computer program has been developed to automatically detect and enhance
the radar echoes. The technique presented is derived within a Bayesian
framework and centers on the construction and analysis of a Likelihood
Function connecting magnetospheric structures and RPI plasmagrams. Once
this technique has been perfected on archival IMAGE data it will be
recoded and used on board the IMAGE spacecraft in a series of tests
thereby greatly facilitating organizations like the National Oceanic and
Atmospheric Administration's (NOAA) Space Environment Center (SEC) to
perform real-time analysis of space weather.

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Presented at Proceedings of SPIE's 14th Annual International AeroSense 
Symposium, April 2000.