Observation of the proton aurora with IMAGE FUV imager and simultaneous ion flux in situ measurements

Gérard, Jean‐Claude; Hubert, Benoît; Meurant, M.; Shematovich, V. I.; Bisikalo, D. V.; Frey, H. U.; Mende, S. B.; Gladstone, G. R.; Carlson, C. W.

doi:10.1029/2001ja900119

Cited by 61 publications

(100 citation statements)

References 28 publications

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“…The drop of the efficiency of the Ly-α excitation is a consequence of the increasing competition between excitation into the HI 2-s state and other processes, such as ionization of the target molecules. These values are close to those derived by Strickland et al (1993) as discussed by Gérard et al (2000Gérard et al ( , 2001. Figure 2 shows the variation of the LBH/Ly-α ratio with the proton mean energy for a proton precipitation with a kappa (κ = 3.5) distribution for a nadir viewing geometry.…”

Section: Model Descriptionsupporting

confidence: 61%

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Remote sensing of the proton aurora characteristics from IMAGE-FUV

Бисикало

Shematovich

Gérard³

et al. 2003

Ann. Geophys.

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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-α 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 protondominated 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 mW m −2 and a mean energy in the range 10-17 keV.

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Section: Model Descriptionsupporting

confidence: 61%

“…As before, this efficiency curve was calculated for monoenergetic (see Fig. 2 in Gérard et al, 2001) and kappa distributions. In the monoenergetic case, the increase in the WIC/SI12 ratio at low energies (Fig.…”

Section: Model Descriptionmentioning

confidence: 99%

Remote sensing of the proton aurora characteristics from IMAGE-FUV

Бисикало

Shematovich

Gérard³

et al. 2003

Ann. Geophys.

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“…Although the low energy ion detectors on both DMSP spacecraft, F13 and F15, are known to be degraded, the decreased sensitivity in the energy range below 1 keV is expected to have only small impact on the calculation of the total particle energy flux. On a global scale the ion contribution to the total particle energy flux is much smaller than that of the electrons, typically no more than 20% (Gérard et al, 2001;Hubert et al, 2002). In addition, the energy range affected by the degradation does not contribute significantly to the ion energy flux in the proton aurora, where the characteristic ion energy is a factor of five or more greater (Newell et al, 2005) than the highest energy of a degraded channel.…”

Section: Particle Energy Fluxmentioning

confidence: 93%

Global observations of electromagnetic and particle energy flux for an event during northern winter with southward interplanetary magnetic field

et al. 2008

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Abstract.The response of the polar ionospherethermosphere (I-T) system to electromagnetic (EM) energy input is fundamentally different to that from particle precipitation. To understand the I-T response to polar energy input one must know the intensities and spatial distributions of both EM and precipitation energy deposition. Moreover, since individual events typically display behavior different from statistical models, it is important to observe the global system state for specific events. We present an analysis of an event in Northern Hemisphere winter for sustained southward interplanetary magnetic field (IMF), 10 January 2002, 10:00-12:00 UT, for which excellent observations are available from the constellation of Iridium satellites, the Super-DARN radar network, and the Far-Ultraviolet (FUV) instrument on the IMAGE satellite. Using data from these assets we determine the EM and particle precipitation energy fluxes to the Northern Hemisphere poleward of 60 • MLAT and examine their spatial distributions and intensities. The accuracy of the global estimates are assessed quantitatively using comparisons with in-situ observations by DMSP along two orbit planes. While the location of EM power input evaluated from Iridium and SuperDARN data is in good agreement with DMSP, the magnitude estimated from DMSP observations is approximately four times larger. Corrected for this underestimate, the total EM power input to the Northern Hemisphere is 188 GW. Comparison of IMAGE FUVderived distributions of the particle energy flux with DMSP plasma data indicates that the IMAGE FUV results similarly locate the precipitation accurately while underestimating the precipitation input somewhat. The total particle input is estimated to be 20 GW, nearly a factor of ten lower than the Correspondence to: H. Korth (haje.korth@jhuapl.edu) EM input. We therefore expect the thermosphere response to be determined primarily by the EM input even under winter conditions, and accurate assessment of the EM energy input is therefore key to achieving a comprehensive understanding of the I-T system, particularly during active times when the energy input increases markedly and expands well equatorward of nominal auroral latitudes.

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“…They concluded a good agreement between predicted and observed emission rates, both in morphology and in intensity. Gérard et al (2001) presented a comparison with SI12 observations for FAST and DMSP satellite overflights. This comparison showed an underestimation of the simulated SI12 response with the latitudinally integrated brightness.…”

Section: The Fuv Imagers and The Auroral Precipitationmentioning

confidence: 99%

“…The imagers are designed to monitor the electron and proton precipitation and discriminate between the two types of particles. Previous studies have shown the quantitative and qualitative validity of FUV instruments from comparisons with in situ auroral particle measurements Gérard et al, 2001;Coumans et al, 2002). Section 2 briefly describes the method used to extract the particle energy and energy flux characteristics from the FUV observations.…”

Section: Introductionmentioning

confidence: 99%

Global auroral conductance distribution due to electron and proton precipitation from IMAGE-FUV observations

et al. 2004

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Abstract. The Far Ultraviolet (FUV) imaging system on board the IMAGE satellite provides a global view of the north auroral region in three spectral channels, including the SI12 camera sensitive to Doppler shifted Lyman-α emission. FUV images are used to produce instantaneous maps of electron mean energy and energy fluxes for precipitated protons and electrons. We describe a method to calculate ionospheric Hall and Pedersen conductivities induced by auroral proton and electron ionization based on a model of interaction of auroral particles with the atmosphere. Different assumptions on the energy spectral distribution for electrons and protons are compared. Global maps of ionospheric conductances due to instantaneous observation of precipitating protons are calculated. The contribution of auroral protons in the total conductance induced by both types of auroral particles is also evaluated and the importance of proton precipitation is evaluated. This method is well adapted to analyze the time evolution of ionospheric conductances due to precipitating particles over the auroral region or in particular sectors. Results are illustrated with conductance maps of the north polar region obtained during four periods with different activity levels. It is found that the proton contribution to conductance is relatively higher during quiet periods than during substorms. The proton contribution is higher in the period before the onset and strongly decreases during the expansion phase of substorms. During a substorm which occurred on 28 April 2001, a region of strong proton precipitation is observed with SI12 around 14:00 MLT at ∼75 • MLAT. Calculation of conductances in this sector shows that neglecting the protons contribution would produce a large error. We discuss possible effects of the proton precipitation on electron precipitation in auroral arcs. The increase in the ionospheric conductivity, induced by a former proton precipitation can reduce the potential drop along field lines in the upward field-aligned currents by creating an opposite polarization electric field. This feedback mechanism possibly reduces the electron acceleration.

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Observation of the proton aurora with IMAGE FUV imager and simultaneous ion flux in situ measurements

Cited by 61 publications

References 28 publications

Remote sensing of the proton aurora characteristics from IMAGE-FUV

Remote sensing of the proton aurora characteristics from IMAGE-FUV

Global observations of electromagnetic and particle energy flux for an event during northern winter with southward interplanetary magnetic field

Global auroral conductance distribution due to electron and proton precipitation from IMAGE-FUV observations

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