Reference : Proton aurora in the cusp
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
Proton aurora in the cusp
Frey, H. U. [> > > >]
Mende, S. B. [> > > >]
Immel, T. J. [> > > >]
Fuselier, S. A. [> > > >]
Claflin, E. S. [> > > >]
Gérard, Jean-Claude mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP) >]
Hubert, Benoît mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP) >]
Journal of Geophysical Research. Space Physics
American Geophysical Union (AGU)
Yes (verified by ORBi)
[en] Magnetospheric Physics: Auroral phenomena (2407) ; Magnetospheric Physics: Energetic particles ; precipitating ; Magnetospheric Physics: Magnetopause ; cusp ; and boundary layers ; Magnetospheric Physics: Solar wind/magnetosphere interactions
[en] Frequently, the Far Ultraviolet Instrument (FUV) on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft observes intense ultraviolet emission from a localized dayside region poleward of the general auroral oval location. This emission is especially distinct in the Doppler-shifted emission of hydrogen atoms produced by precipitating protons. We interpret this as a direct signature of proton precipitation into the cusp after reconnection of magnetospheric lobe field lines. This cusp signature appears only when the interplanetary magnetic field (IMF) has a positive northward B[SUB]z[/SUB] component. However, the intensity of the precipitation, and hence the intensity of UV emission, is not controlled by the magnitude of B[SUB]z[/SUB] but rather by the solar wind dynamic pressure. A statistical analysis of 18 cases observed in summer and fall 2000 shows good correlation between the UV intensity and the dynamic pressure and between the location in local time and the IMF B[SUB]y[/SUB] component. A quantitative analysis of observations from all three FUV subinstruments allows for an estimate of proton and electron energy fluxes during these times. In general, these estimates agree with results from in situ measurements by spacecraft and show that during these times, protons may contribute significantly to the overall energy deposition into the cusp.
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