MGS electron density profiles: Analysis of the peak magnitudes

Fox, Jane L.; Yeager, Katherine E.

doi:10.1016/j.icarus.2008.12.002

Cited by 64 publications

(95 citation statements)

References 41 publications

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“…From this equation we see that in Chapman theory, the maximum density varies as the square root of cos(v) and as the square root of the solar photon flux F 1 . In a previous paper, we investigated the behavior of the magnitudes of the F 1 and E peaks of the electron density profiles of the martian ionosphere in the northern hemisphere as measured by the MGS RSS (Fox and Yeager, 2009). We analyzed the behavior of the peak densities as a function of solar zenith angle and solar flux, including in our analysis one radio occultation profile per Earth day: that which exhibited the median F 1 peak density for that day.…”

Section: Essentials Of Chapman Theorymentioning

confidence: 99%

“…Since the peak height varies quite substantially with planetocentric longitude, in order to obtain good longitudinal coverage, many more profiles were required than those of our previous study of the peak magnitudes (Fox and Yeager, 2009). We have divided the east longitude range from 0°to 360°into 36 bins, and we have assigned each occultation profile to the appropriate 10°longitude bin.…”

Section: Overview Of This Studymentioning

confidence: 99%

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MGS electron density profiles: Analysis and modeling of peak altitudes

Fox

Weber

2012

Icarus

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Section: Essentials Of Chapman Theorymentioning

confidence: 99%

Section: Overview Of This Studymentioning

confidence: 99%

MGS electron density profiles: Analysis and modeling of peak altitudes

Fox

Weber

2012

Icarus

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“…Nevertheless, to explore this topic further, we repeated this analysis for the M2 peak densities and found an exponent of 0.26 ± 0.06. Fox and Yeager (2009) reported a very similar value: an exponent of 0.263 ± 0.008. There does not appear to be any systematic difference between Mariner 9 and Mars Global Surveyor results for how peak electron densities depend on solar irradiance.…”

Section: M1 Peak Electron Density and Solar Irradiancementioning

confidence: 70%

“…9 shows that the extended mission data are generally consistent with the primary mission data. In their analysis of Mars Global Surveyor data, Fox and Yeager (2009) found an exponent of 0.462 ± 0.012. Due to the large uncertainty on the Mariner 9 exponent, these two exponents are formally indistinguishable.…”

Section: M1 Peak Electron Density and Solar Irradiancementioning

confidence: 99%

“…Previous work found that the dust storm did not affect M2 peak densities (Hantsch and Bauer 1990). Fox and Yeager (2009) investigated the dependence of M1 electron density on solar irradiance using Mars Global Surveyor electron density profiles. Here, we test whether their findings are consistent with analysis of the independent Mariner 9 dataset.…”

Section: M1 Peak Electron Density and Solar Zenith Anglementioning

confidence: 99%

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Recovery and validation of Mars ionospheric electron density profiles from Mariner 9

2015

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Electron density profiles from the ionosphere of Mars that were obtained by the Mariner 9 radio occultation experiment in 1971-1972 have unique scientific value because they extend to higher altitudes than comparable datasets and were acquired during a tremendous dust storm that had substantial and poorly understood effects on the ionosphere. Yet these profiles are not publicly available in an accessible format. Here, we describe the recovery of these profiles, which are made available as part of this article. The validity of the profiles was tested by using them to explore the effects of a dust storm on the topside ionosphere, the morphology of the topside ionosphere, the behavior of the M1 layer, and possible meteoric layers. The dust storm that waned over the course of the primary mission (November-December 1971) had major effects on the ionosphere of Mars. It elevated the M1 and M2 layers of the ionosphere by 20-30 km, but the separation of the two layers stayed fixed throughout the primary mission, which suggests that the neutral atmosphere at these altitudes was not heated during the dust storm. However, the altitude of the 1500 cm −3 density level, a proxy for the top of the ionosphere, decreased steadily by 74 ± 12 km over the course of the primary mission. Mariner 9 observations of the topside ionosphere differ from comparable Mars Express observations. Compared to Mars Express, the Mariner 9 data, which were acquired during a period of relatively high solar wind dynamic pressure, have lower densities at high altitudes. They are also more likely to have a "one scale height" morphology than a "two scale height" morphology. The peak density of the M1 layer depends on solar zenith angle and solar irradiance similarly to previous studies with Mars Global Surveyor observations, which indicates that dust storms do not affect the behavior of the peak density. No clear meteoric layers were identified.

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Predictions of electron temperatures in the Mars ionosphere and their effects on electron densities

Withers

Fallows

Matta

2014

Geophysical Research Letters

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Observations of peak electron densities in the Mars ionosphere are well fit by a simplistic theory that assumes the electron temperature, Te, at the peak remains constant as solar zenith angle, χ, changes. However, Te ought to vary with both altitude and χ. Here we use an existing numerical model of ionospheric energetics, which includes both vertical and diurnal variations in temperatures, to predict that Te at the ionospheric peak is relatively independent of χ. This model accurately predicts the observed dependence of peak electron density on χ, whereas predictions using Viking‐based electron temperatures that are held constant with time do not. A simplified analytic model is developed to interpret these results further. It predicts that the difference between electron and neutral temperatures is proportional to the ratio of electron heating rate to electron production rate and proportional to the square root of solar irradiance.

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MGS electron density profiles: Analysis of the peak magnitudes

Cited by 64 publications

References 41 publications

MGS electron density profiles: Analysis and modeling of peak altitudes

MGS electron density profiles: Analysis and modeling of peak altitudes

Recovery and validation of Mars ionospheric electron density profiles from Mariner 9

Predictions of electron temperatures in the Mars ionosphere and their effects on electron densities

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