Numerical predictions of aerosol charging and electrical conductivity of the lower atmosphere of Mars

Michael, M.; Barani, Mohammad; Tripathi, Sachchida Nand

doi:10.1029/2006gl028434

Cited by 20 publications

(25 citation statements)

References 18 publications

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“…the neutral aerosols have a maximum concentration whereas the aerosols with maximum charges have their minimum concentration. It was also noted by Michael et al (2007) that the steady-state concentration of the aerosols with positive charges is somewhat higher than the corresponding negatively charged aerosols. This is because the positive ions have higher mobility and are attached to the aerosols faster.…”

Section: Marsmentioning

confidence: 93%

“…Michael et al (2007) showed that the concentration of charged aerosols decreases as the altitude increases. The aerosols are charged up to 36 elementary charges (i.e.…”

Section: Marsmentioning

confidence: 99%

“…Between 47 and Fig. 7 Effect of aerosols in the atmospheric conductivity in (a) Venus (Borucki et al 1982), Mars (Michael et al 2007), (b) Titan (Borucki et al 2006), and (c) Jupiter (Whitten et al 2008). Red lines are conductivities of the clear atmospheres and black lines are conductivities in the presence of aerosols.…”

Section: Electrical Conductivitymentioning

confidence: 99%

“…Mars: Michael et al (2007) studied the electrical conductivity in the night-time atmosphere of Mars. The maximum variation in conductivity was observed close to the surface (dropped by a factor of five) of the planet and effect of aerosols becomes negligible for altitudes greater than 50 km.…”

Section: Electrical Conductivitymentioning

confidence: 99%

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Profiles of Ion and Aerosol Interactions in Planetary Atmospheres

2008

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In planetary atmospheres the nature of the aerosols varies, as does the relative importance of different sources of ion production. The nature of the aerosol and ion production is briefly reviewed here for the atmospheres of Venus, Mars, Jupiter and Titan using the concepts established for the terrestrial atmosphere. Interactions between the ions formed and aerosols present cause (1) charge exchange, which can lead to substantial aerosol charge and (2) ion removal. Consequences of (1) are that (a) charged aerosol are more effectively removed by conducting liquid droplets than uncharged aerosol and (b) particle-particle coagulation rates are modified, influencing particle residence times in the relevant atmosphere. Consequences of (2) are that ions are removed in regions with abundant aerosol, which may preclude charge flow in an atmosphere, such as that associated with an atmospheric electrical circuit. In general, charge should be included in microphysical modeling of the properties of planetary aerosols.

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Section: Marsmentioning

confidence: 93%

“…Michael et al (2007) showed that the concentration of charged aerosols decreases as the altitude increases. The aerosols are charged up to 36 elementary charges (i.e.…”

Section: Marsmentioning

confidence: 99%

Section: Electrical Conductivitymentioning

confidence: 99%

Section: Electrical Conductivitymentioning

confidence: 99%

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Profiles of Ion and Aerosol Interactions in Planetary Atmospheres

2008

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“…It decreases by more than two orders of magnitude compared to the simple model of ion-neutral chemistry of Molina-Cuberos et al (2002) to be less than ∼0.5 e cm −3 at ground with the ∼100 e cm −3 peak at 35 km lifted to ∼45 km, and also reduced by two orders of magnitude at ∼1 e cm −3 . Michael et al (2007 comprehensively modelled the role of aerosols on the charged particle distribution and conductivity in the lower atmosphere using aerosol properties (Chassefière et al 1995). These studies were performed for both night-time and daytime conditions when dust particles are photo-ionized by low energy (∼6 eV) solar UV that reach the Martian surface and produce a photo-electron population whose properties were taken from the work of Grard (1995).…”

Section: Martian Conductivity Profiles and Relaxation Timescalesmentioning

confidence: 99%

Applications of Electrified Dust and Dust Devil Electrodynamics to Martian Atmospheric Electricity

et al. 2016

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Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kV m −1 to 100 kV m −1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m −1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)-B R.G. Harrison

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Long‐term variability of dust optical depths on Mars during MY24–MY32 and their impact on subtropical lower ionosphere: Climatology, modeling, and observations

Sheel

Haider

2016

JGR Space Physics

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Dust optical depths (τ) for nine Martian years (MY24–MY32) in the subtropical region (25–35°S) have been used to classify distinct dust scenarios. These data are based on observations at 9.3 µm from the Mars Global Surveyor and Mars Odyssey missions and encompass the regional dust storms which occur every year around solar longitude (Ls) ~ 220° and the two major dust storms of MY25 and MY28. Constrained by these observations and the Mars Climate Sounder observations of detached dust layers, we estimate altitude profiles of dust concentrations. We discuss the characteristics of dust aerosol particles of different size between 0.2 and 3.0 µm by assuming a modified gamma distribution. We then use a comprehensive ion‐dust model to calculate ion densities and conductivities in the lower ionosphere of Mars in the absence of dust storm at τ = 0.1 and Ls = 150° and for three dust storm periods viz., (1) major dust storm at τ = 1.7 and Ls = 210°, (2) major dust storm at τ = 1.2 and Ls = 280°, and (3) regional dust storm at τ = 0.5 and Ls = 220°. The model with 12 neutral species considers galactic cosmic rays as a source of ionization. Results show that the density of the dominant hydrated cluster ions and the electrical conductivity are reduced by an order of magnitude near the surface for a few months until the dust storm settles down to its normal condition.

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Numerical predictions of aerosol charging and electrical conductivity of the lower atmosphere of Mars

Cited by 20 publications

References 18 publications

Profiles of Ion and Aerosol Interactions in Planetary Atmospheres

Profiles of Ion and Aerosol Interactions in Planetary Atmospheres

Applications of Electrified Dust and Dust Devil Electrodynamics to Martian Atmospheric Electricity

Long‐term variability of dust optical depths on Mars during MY24–MY32 and their impact on subtropical lower ionosphere: Climatology, modeling, and observations

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