High Latitude Oxygen LENA

Wilson, G. R., T. E. Moore and M. Collier

One of the primary goals of the LENA instrument on IMAGE is to study
outflowing ions produced at high latitudes in the auroral zone and cusp
regions. The energization of H+ and O+ ions to energies in the 10 eV to
1 keV range in these regions should produce copious fluxes of low
energy neutral atoms (LENA) after some of the accelerated ions charge
exchange with thermospheric hydrogen and oxygen. Intense neutral fluxes
are observed by the instrument during high latitude IMAGE perigee
passes but their connection to the auroral zone is not clear because
the emission patterns lack a clear auroral zone signature. The data do,
however, support the idea that the neutral fluxes seen are low energy
(<40 eV) and primarily oxygen in composition. The behavior of such
particles will be discussed with a view toward explaining how the
auroral zone could be the source of the observed diffuse emission
patterns. In the end though it is unlikely that the auroral zone can
account for all that is seen and so some other sources will be needed.

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