Summary of Quantitative Interpretation of Image Far Ultraviolet Auroral Data

Frey, H. U., T. J. Immel, S. B. Mende, J.-C. Gerard, B. Hubert, S. Habraken,
J. Spann, R. Gladstone

	Direct imaging of the magnetosphere by instruments on the IMAGE spacecraft
are supplemented by simultaneous observation of the global aurora in three
far ultraviolet (FUV) wavelength bands. The purpose of the multi-wavelength
imaging is to study the global auroral particle and energy input from the
magnetosphere into the atmosphere and this paper provides a method of
quantitative interpretation of the FUV measurements. The Wide-Band Imaging
Camera (WIC) provides broad band ultraviolet images of the aurora for
maximum spatial and temporal resolution by imaging the nitrogen lines and
bands between 140 and 180 nm wavelength. The Spectrographic Imager (SI), a
dual wavelength channel monochromatic imager, images the Doppler-shifted
Lyman alpha, the proton-induced aurora component in SI12 channel and auroral
135.6 nm OI emission in the SI13 channel. From the SI12 Doppler shifted
Lyman alpha measurements it is possible to obtain the proton flux provided
some reasonable assumptions are made regarding the mean energy of the
protons. Knowledge of the proton (flux and energy) component allows the
calculation of the intensities produced by the protons in the WIC and SI-13
instruments. Comparison of the electron produced WIC and SI13 signal
provides a measure of the electron mean energy as long as the atmosphere is
relatively un-disturbed. In order to be able to do this reliable modeling
emission modeling and instrument calibrations are needed. In flight
calibration using stars were used to validate the pre-flight laboratory
calibrations and in general very good agreement was found.

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To be presented at the Magnetospheric Imaging Workshop, 
Yosemite National Park, California, U.S.A., Feb. 5-8, 2002.