Storm-time plasma signatures observed by IMAGE/MENA and comparison with a
global physics-based model

M. H. Denton, V. K. Jordanova, M. G. Henderson, R. M. Skoug, M. F. Thomsen,
C. J. Pollock, S. Zaharia and H. O. Funsten.


We present energetic neutral atom (ENA) fluxes measured using the medium
energy neutral atom (MENA) imager on-board the IMAGE satellite for the
geomagnetic storm of 21 October 2001 at energies of 6 and 12 keV.  These ENA
fluxes indicate strong low altitude ENA emissions close to the Earth and a
nightside peak in ENA emissions close to local midnight.  The observed ENA
fluxes are compared with theoretical ENA fluxes calculated using the ring
current-atmosphere interaction (RAM) model at the same energies observed by
MENA.  We find good qualitative agreement between the observations and the
model both of which show a peak in ENA emissions on the nightside, close to
local midnight.

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Submitted to Journal of Geophysical Research, 2005