High resolution daytime photoelectron energy spectra from AE‐E

Doering, J. P.; Peterson, W. K.; Bostrom, C. O.; Potemra, T. A.

doi:10.1029/gl003i003p00129

Cited by 75 publications

(48 citation statements)

References 6 publications

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“…Figure 1 shows the predicted SE distribution from 0 to 100 eV (from Khazanov (1)). The shape of this distribution is consistent with the observations of Doering et al (2,3) with their photoelectron spectrometer (PES) on NASA's AE-C and AE-E satellites. Of particular interest in this paper is the broad peak in the low-energy region at 5 eV and the multiplicity of narrow peaks seen between 15 and 35 eV -these features still need measurements at higher resolutions to take full advantage of their existence to understand the nature of photoelectrons in the ionosphere.…”

Section: Introductionsupporting

confidence: 86%

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A numerical study of the 30° parallel plate analyzer for ionospheric electron spectroscopy

Herrero

Khazanov

2013

Radiation Effects and Defects in Solids

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A charged-particle spectrometer is described that uses a configuration of the 30 • parallel plate analyzer that differs from the previous one in that the entrance slit sits at the base plate while the exit slit is, as before, displaced to a point beneath the base plate. This approach preserves the second-order focusing previously found, yielding energy resolution of 0.01 − 0.3 eV for electrons in the energy range 1 − 30 eV. This is sufficient to address two identified problems in ionospheric electron energy distributions. In addition, the analyzer provides focusing of electron energies along a flat plane to operate as an energy spectrograph with a geometric factor of 10 −3 cm 2 -sr at an energy resolution K/K = 0.01; the performance required for very high resolution photoelectron spectroscopy in the ionospheric plasma.

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Section: Introductionsupporting

confidence: 86%

“…This feature is evident in Doering's data (2,3) and in the sounding rocket investigations of Hays and Sharp (4) and McMahon and Heroux (5,6). This structure reaches a maximum in prominence in the 130-150 km region and gradually diminishes with increasing altitude, disappearing in the 200-250 km region.…”

Section: Introductionmentioning

confidence: 65%

A numerical study of the 30° parallel plate analyzer for ionospheric electron spectroscopy

Herrero

Khazanov

2013

Radiation Effects and Defects in Solids

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“…These peaks have been identified clearly also by satellite observations (DOERING et al, 1975(DOERING et al, , 1976LEE et al, 1980a). The drop in the spectrum above 60eV which is due to the absence of significant solar radiation at energies higher than 70-80eV has also been identified previously (MuKAI and HIRAO, 1975;DOERING et al, 1975DOERING et al, , 1976LEE et al, 1980a). Therefore, the features of the photoelectron energy distribution observed from the EXOS-C satellite are generally consistent with the previous results.…”

Section: (C)supporting

confidence: 79%

“…MUTAI andHIRAO (1973, 1975) originally found the existence of several peaks in the energy range from 20 to 30eV at lower altitudes, which could be attributed to photoelectrons emitted from N2 and O by the intense solar He II (304A) radiation, and which were smeared out due to Coulomb collisions with ambient thermal electrons at higher altitudes. These peaks have been identified clearly also by satellite observations (DOERING et al, 1975(DOERING et al, , 1976LEE et al, 1980a). The drop in the spectrum above 60eV which is due to the absence of significant solar radiation at energies higher than 70-80eV has also been identified previously (MuKAI and HIRAO, 1975;DOERING et al, 1975DOERING et al, , 1976LEE et al, 1980a).…”

Section: (C)supporting

confidence: 52%

Initial observation of low-energy charged particles by satellite OHZORA (EXOS-C)

Mukai

Kaya

Kubo

et al. 1985

J. geomagn. geoelec

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The low-energy particle experiment (ESP) on the EXOS-C satellite was designed to measure the energy spectrum and the pitch-angle distribution of electrons over the energy range of 6 eV to 16 keV and positive ions from 200 eV to 16 keV. The experiment has been successful and it has revealed global characteristics of ionospheric photoelectrons and magnetospheric energetic particles over a wide range of latitude, longitude, altitude (350-850km) and local time. The precipitation of auroral particles is observed at latitudes higher than the trapping boundary of higher-energy particles. The electron precipitation pattern is diffuse in the dayside auroral region, whereas it is quite discrete on the nightside. The energy spectrum of ions precipitating into the auroral region is found to be generally harder than the corresponding electrons. Energetic electrons with energies of 10-100keV have also been detected at dusk hours near the equator. The nature of these electrons is not yet known. The energy spectrum of photoelectrons is found to have a peak in an energy range from 20 to 30eV and a sharp cutoff near 60eV. However, the spectral shape in the energy range of 20 to 30eV is found to vary significantly depending on latitude, longitude and local time. A large peak at 20-30eV is observed occasionally over the region of the South-Atlantic geomagnetic anomaly.

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“…A unique signature of photoelectrons is the presence of peak structures in the suprathermal electron spectra, associated with photoionization of ambient atmospheric neutrals by the strong solar HeII 30.4 nm line, as well as other lines such as FeIX, X at 17.1 nm [e.g., Mantas and Hanson, 1979;Fox and Dalgarno, 1979]. The detection and identification of such peaks have been reported for measurements of suprathermal electron intensity in the sunlit ionosphere of Earth [e.g., Doering et al, 1976;Nagy et al, 1977;Solomon et al, 2001] and Titan [e.g., Galand et al, 2006;Coates et al, 2007;Robertson et al, 2009] associated with N 2 photoionization, and on Mars [e.g., Frahm et al, 2006a] and Venus [Coates et al, 2008[Coates et al, , 2011 associated with CO 2 /O photoionization. Similar spectral signatures associated with H 2 are also expected on Jovian planets [e.g., Waite et al, 1983;Galand et al, 2009].…”

mentioning

confidence: 99%

Suprathermal electron spectra in the Venus ionosphere

et al. 2011

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[1] In this study, a multistream kinetic model is used to derive the suprathermal electron intensity in the Venus ionosphere, to be compared with the observations made by the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) instrument onboard Venus Express (VEx) on 18 May 2006. Input parameters of the model are chosen to be consistent with the detailed ephemeris information. We consider two cases for the magnetic field line configuration. The first assumes vertical magnetic field lines, while in the second the configuration is consistent with the VEx Magnetometer (MAG) measurements for that particular orbit. The model calculations suggest that the energy spectrum of suprathermal electrons not only depends on the local photoelectron production but is also strongly influenced by transport as well as energy degradation. We confirm the postulation of Coates et al. (2008) (2008). The model results indicate that the condition of local equilibrium is satisfied for suprathermal electrons below ∼155 km on Venus. However, transport becomes effective at higher altitudes, significantly altering the secondary electron production rate and leading to strongly anisotropic suprathermal electron flow. For the case with the MAG-derived, slanted magnetic field configuration, we make a data-model comparison in terms of both the absolute magnitude of the suprathermal electron intensity and the appearance of spectral peaks. The comparison suggests that the actual magnetic field lines are probably inclined more vertically than a simple extrapolation from the MAG measurements.

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High resolution daytime photoelectron energy spectra from AE‐E

Cited by 75 publications

References 6 publications

A numerical study of the 30° parallel plate analyzer for ionospheric electron spectroscopy

A numerical study of the 30° parallel plate analyzer for ionospheric electron spectroscopy

Initial observation of low-energy charged particles by satellite OHZORA (EXOS-C)

Suprathermal electron spectra in the Venus ionosphere

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