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Ann. Geophys., 21, 2165-2173, 2003
www.ann-geophys.net/21/2165/2003/
© European Geosciences Union 2003
Remote sensing of the proton aurora characteristics from IMAGE-FUV
D. V. Bisikalo1, V. I. Shematovich1, J.-C. Gérard2, M. Meurant2, S. B. Mende3, and H. U. Frey3
1Institute of Astronomy, RAS, Moscow, Russia
2LPAP, Université de Liège, Belgium
3SSL, University of California, Berkeley, CA, USA
Abstract. The combination of
simultaneous global images of the north polar region obtained with the IMAGE-FUV
imaging system makes it possible to globally map the properties of the electron
and proton auroral precipitation. The SI12 imager, which observes the
Doppler-shifted Lyman-a emission, provides a global
snapshot of the proton aurora every 2 min. These images may be combined with
those from the Wide-band Imaging Camera (WIC), to remotely characterize the
proton precipitation in proton-dominated auroral structures frequently observed
in the afternoon and pre-midnight sectors at the equatorial edge of the auroral
oval. It is shown that both the proton energy flux and the mean energy
determined by this method are in good agreement with coincident in situ
measurement from low altitude satellites carrying proton detectors, when taking
into account the different spatial resolution of the two types of observations.
Four proton-dominated cases are illustrated in this study. They belong to two
categories of proton auroral features: (i) hydrogen arcs known to occur in the
evening sector equatorward of the electron oval and (ii) detached proton arcs
observed with IMAGE-FUV in the afternoon sector following changes in
orientation of the interplanetary magnetic field. They are characterized by a
proton flux of 0.5–2 mWm-2 and a mean energy in the range 10–17
keV.
Key words. Magnetospheric physics (auroral
phenomena; energetic particles, precipitating; magnetopause, cusp, arid
boundary layers)
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