Far Ultraviolet Imaging from the Image Spacecraft. 3. Spectral Imaging of Lyman-∝ and OI 135.6 nm

Mende, S. B.; Heetderks, H.; Frey, H. U.; Stock, Joseph M.; Lampton, M.; Geller, S. P.; Abiad, R.; Siegmund, Oswald H. W.; Habraken, Serge; Renotte, Étienne; Jamar, C.; Rochus, Pierre; Gérard, Jean‐Claude; Sigler, Robert D.; Lauche, H.

doi:10.1007/978-94-011-4233-5_10

Cited by 136 publications

(172 citation statements)

References 28 publications

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“…The focus of this study remains, therefore, on the 2002 observations. The Spectrographic Imager (SI) on board IMAGE has two FUV wavelength channels, one to obtain images of Dopplershifted hydrogen emissions at 121.8 nm, originating in the proton aurora, and another to spectrally separate and obtain images of the 135.6 nm emission of O I (Mende et al, 2000). In the terrestrial environment, this emission of O I generally has two causes; either excitation by impact of energetic electrons produced by solar Extreme-ultraviolet (EUV) photoionization or ionization through precipitation of auroral particles, or by radiative recombination of ionospheric O + .…”

Section: Instrumentation: Image/fuv Si-13mentioning

confidence: 99%

Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles

et al. 2004

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Abstract. Space-based measurements from an imager aboard the high-apogee NASA-IMAGE satellite allows for global-scale observations of nightside ionospheric densities and structure. Such a view cannot be provided by imagers in near-Earth orbit or based on the ground. The IMAGE Spectroscopic Imager (SI) isolates the Far-ultraviolet (FUV) O I 135.6 nm emission which is produced through radiative recombination of O + . These observations clearly show the distribution of FUV emissions of the equatorial airglow bands over the range of local times between the evening terminator to points well after midnight. Determination of plasma drift speeds in these local time sectors is performed by identification and subsequent tracking of localized depressions in the FUV emissions. This determination is made for nearly 200 plasma bubbles in the March-May period of 2002. Important findings of this study include (1) an unambiguous association between D st and zonal plasma drift speeds, and (2) a longitudinal dependence of the zonal plasma drift speeds, with a peak around the Indian sector. The first effect is attributed to penetrating ring current electric fields, while the second is apparently due to a longitudinal variability in the vertical polarization electric fields that directly affects the zonal plasma drift speeds.

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Section: Instrumentation: Image/fuv Si-13mentioning

confidence: 99%

Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles

et al. 2004

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“…The IMAGE SI12 has a gorill system to reject the geocoronal Ly cx emission at 1215.6 A and allow a fraction of the broad auroral Ly cx line profile [Mende et al, 2000a[Mende et al, , 2000b. Since this emission is emitted by excited fast H atoms, the line profile for a given observation geometry depends on the energy spectrum of the incident auroral protons and their pitch angle distribution.…”

Section: Lyman Et Line Profile and Si12 Responsementioning

confidence: 99%

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

Gérard¹,

Hubert²,

Meurant³

et al. 2001

J. Geophys. Res.

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“…The Polar UVI oxygen filters each had 5 nm wide bandpasses and average out-of-waveband blocking of better than 3×10 −3 % (Zukic et al 1993), but the filters required a 45 • angle of incidence, increasing instrument complexity -the Polar UVI mass of 21 kg was substantially larger than the 7 kg (9.1 kg) total mass for the Viking (Freja) cameras (Torr et al 1995;Anger et al 1987;Murphree et al 1994). Good FUV wavelength discrimination may also be achieved with the use of imaging spectrometers, such as the Spectrographic Imager (SI) on IMAGE (Mende et al 2000; IMAGE also carried a Wideband Imaging Camera (WIC) based on the Viking/Freja Cassegrain design) but, as with the Polar UVI filters, this comes at the cost of increased instrument complexity and reduced throughput. Typically, an imaging spectrograph will have a narrow field of view and must therefore build up auroral images by scanning over the auroral region, and so is unable to provide an instantaneous view of auroral morphology in the same way that a conventional imager can.…”

Section: Introductionmentioning

confidence: 99%

Isolating auroral FUV emission lines using compact, broadband instrumentation

Molyneux

Bannister

Bunce

et al. 2014

Planetary and Space Science

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Images of auroral emissions at far ultraviolet (FUV, wavelengths are useful tools with which to study magnetospheric-ionospheric coupling, as the scattered sunlight background in this region is low, allowing both dayside and nightside auroras to be imaged simultaneously.The ratio of intensities between certain FUV emission lines or regions can be used to characterise the precipitating particles responsible for auroral emissions, and hence is a useful diagnostic of magnetospheric dynamics. Here, we describe how the addition of simple transmission filters to a compact broadband imager design allows far ultraviolet emission ratios to be deduced while also providing large-scale instantaneous images of the aurora. The low mass and volume of such an instrument would make it well-suited for both small satellite Earth-orbiting missions and larger outer planet missions from which it could be used to characterise the tenuous atmospheres observed at several moons, as well as studying the auroral emissions of the gas giants. We present a study to investigate the accuracy of a technique to allow emission line ratio retrieval, as applied to the OI 130.4 nm and 135.6 nm emissions at Ganymede. The ratio of these emissions provides information about the atmospheric composition, specifically the relative abundances of O and O 2 .Using modelled FUV spectra representative of Ganymede's atmosphere, based on observations by the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS), we find that the accuracy of the retrieved ratios is a function of the magnitude of the ratio, with the best measurements corresponding to a ratio of ∼1.3.

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Far Ultraviolet Imaging from the Image Spacecraft. 3. Spectral Imaging of Lyman-∝ and OI 135.6 nm

Cited by 136 publications

References 28 publications

Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles

Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles

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

Isolating auroral FUV emission lines using compact, broadband instrumentation

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