The ionosphere of Venus: Strongest control by photo-chemical-equilibrium in the solar system, with implications for exospheric temperatures

Mendillo, M.; Trovato, Jeffrey; Narvaez, C.; Withers, Paul; Pätzold, M.; Peter, Kerstin; Tellmann, S.; Häusler, B.

doi:10.1016/j.icarus.2020.113870

Cited by 2 publications

(6 citation statements)

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“…The PCE equations at that fixed distance from the Sun are then used to formulate the PCE model. This protocol is fully described in our study of Venus' ionosphere (Mendillo et al., 2020). The end result for maximum electron density ( N max ), that also holds for TEC, is

{N}_{\mathrm{max}}\,\mathrm{a}\mathrm{n}\mathrm{d}\,\mathrm{T}\mathrm{E}\mathrm{C}\,\sim \,\sqrt{{F}_{\mathrm{e}\mathrm{f}\mathrm{f}\,}\times \mathrm{cos}(\mathrm{S}\mathrm{Z}\mathrm{A})}

…”

Section: Review Of Photo‐chemical‐equilibrium Characteristics In An I...mentioning

confidence: 99%

“…When observations are tested using the parameterization in Equation 2, a high correlation coefficient (CC > 0.90) occurs at Earth, Mars, and Venus (Mendillo et al, 2016(Mendillo et al, , 2020.…”

Section: Approaches To Semi-empirical Modelingmentioning

confidence: 99%

“…TEC has also been studied at Saturn (Mendillo et al, 2018) and Venus (Mendillo et al, 2020) using height-integrated ROX profiles.…”

Section: Specific Characteristics Of Jupiter's Electron Density Profilesmentioning

confidence: 99%

“…The radar on the Mars Reconnaissance Orbiter also provided global information about TEC at Mars (Campbell & Watters, 2016; Mendillo et al., 2017). TEC has also been studied at Saturn (Mendillo et al., 2018) and Venus (Mendillo et al., 2020) using height‐integrated ROX profiles.…”

Section: Pioneer and Voyager Era Observationsmentioning

confidence: 99%

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Jupiter's Enigmatic Ionosphere: Electron Density Profiles From the Pioneer, Voyager, and Galileo Radio Occultation Experiments

et al. 2022

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Radio occultation experiments on the Pioneer and Voyager missions obtained the first seven electron density profiles Ne(h) of Jupiter's ionosphere. We use the five complete Ne(h) observations to assess patterns and processes linked to photo‐chemical‐equilibrium (PCE) theory, modeled previously to be the domain below ∼1,000 km. We find that the Ne(h) profiles are highly structured and identification of the maximum electron density and its height do not follow PCE expectations for layers produced by the Sun's soft X‐rays and extreme ultraviolet. Pre‐dawn profiles often show larger electron densities than dusk‐side profiles, inconsistent with simple chemical decay throughout nighttime. We examined total electron content (TEC) values, defined as Ne(h) integrated up to a 3,500 km height, and found statistically significant TEC correlations (correlation coefficient ∼0.85) with solar fluxes over solar cycle time scales. The subsequent set of 25 Ne(h) profiles obtained during the Galileo mission confirmed all of the variability patterns found by Pioneer and Voyager. Most notable was a weaker solar cycle pattern for TEC. Yet, different solar cycle characteristics during the three missions cannot explain their different values for TEC. Average Ne(h) profiles from the early missions (P10‐11; V1‐2) revealed a three‐layer system that was confirmed by average Galileo results. Models using faster electron‐ion recombination caused by vibrationally excited H2 converting atomic ions to molecular ions could lead to enhanced removal of plasma near ∼1,000 km, and thus the topside layer formation that often appears at ∼1,500 km, while XUV radiation likely produces the two lower layers in the PCE domain.

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{N}_{\mathrm{max}}\,\mathrm{a}\mathrm{n}\mathrm{d}\,\mathrm{T}\mathrm{E}\mathrm{C}\,\sim \,\sqrt{{F}_{\mathrm{e}\mathrm{f}\mathrm{f}\,}\times \mathrm{cos}(\mathrm{S}\mathrm{Z}\mathrm{A})}

…”

Section: Review Of Photo‐chemical‐equilibrium Characteristics In An I...mentioning

confidence: 99%

Section: Approaches To Semi-empirical Modelingmentioning

confidence: 99%

“…TEC has also been studied at Saturn (Mendillo et al, 2018) and Venus (Mendillo et al, 2020) using height-integrated ROX profiles.…”

Section: Specific Characteristics Of Jupiter's Electron Density Profilesmentioning

confidence: 99%

Section: Pioneer and Voyager Era Observationsmentioning

confidence: 99%

See 2 more Smart Citations

Jupiter's Enigmatic Ionosphere: Electron Density Profiles From the Pioneer, Voyager, and Galileo Radio Occultation Experiments

et al. 2022

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“…While there have been no in situ measurements from the Venusian ionosphere at solar minimum, there have been radio occultation (remote sensing) measurements over the solar cycle from which total electron density may be inferred (Gringauz et al., 1979; Imamura et al., 2017; Knudsen et al., 1987; Mendillo et al., 2020). While this is a powerful and widely available technique, radio occultation can only provide a line‐of‐sight integrated measurement of the total electron density, and integrates a wide range of solar zenith angles together (Brace et al., 1997).…”

Section: Comparison To Pioneer Venus Orbiter Observations Near Solar Maximummentioning

confidence: 99%

Depleted Plasma Densities in the Ionosphere of Venus Near Solar Minimum From Parker Solar Probe Observations of Upper Hybrid Resonance Emission

Collinson

Ramstad

Glocer

et al. 2021

Geophysical Research Letters

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The ionosphere of Venus: Strongest control by photo-chemical-equilibrium in the solar system, with implications for exospheric temperatures

Cited by 2 publications

References 36 publications

Jupiter's Enigmatic Ionosphere: Electron Density Profiles From the Pioneer, Voyager, and Galileo Radio Occultation Experiments

Jupiter's Enigmatic Ionosphere: Electron Density Profiles From the Pioneer, Voyager, and Galileo Radio Occultation Experiments

Depleted Plasma Densities in the Ionosphere of Venus Near Solar Minimum From Parker Solar Probe Observations of Upper Hybrid Resonance Emission

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