Global Ionospheric Ion Outflow

S.A. Fuselier


Ionospheric outflow from the EarthÕs auroral region is a dramatic example of
large-scale magnetosphere-ionosphere coupling driven by microphysics. In situ
observations have been used to create statistical sampling of this outflow and
investigate outflow on long timescales (months). Neutral atom imaging provides
the possibility to investigate global outflow on much shorter timescales, in
particular on the timescale of a magnetospheric substorm (hours). Although there
are still several characteristics of ionospheric outflow that make the
interpretation of neutral atom images difficult, recent correlation of outflow
with precipitation of low energy (<1 keV) electrons has been used to create
relatively simple outflow models that are consistent with the neutral atom
images. This talk focuses on images from the Low Energy Neutral Atom (LENA)
imager on the IMAGE spacecraft. In particular, two relatively simple, but
important parameters are derived for substorm recovery times. The first is the
local time extent of the ionospheric outflow and the second is the variability
in this local time extent. Particular emphasis is placed on comparing the local
time extent of the outflow with the location and local time extent of the cusp.

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Global Aspects of Magnetosphere-Ionosphere Coupling, 2006 Yosemite Workshop, 
Yosemite National Park, CA, USA, 7-10 February 2006