Precipitation‐powered mechanisms of cloud electrification

Mathpal, K. C.; Varshneya, N. C.; Dass, N. D. Hari

doi:10.1029/rg018i002p00361

Cited by 16 publications

(15 citation statements)

References 74 publications

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“…Consequently, aeolian features that have a mass stratification process (upward winds, downward gravity) will develop well‐separated charging centers in the dust storm, giving rise to an overall storm dipole electric field. The process is similar to the situation in thunderstorms where light ice of positive charge is blown upward relative to heavier, negatively charged ice and rain [ Mathpal et al , 1980; Volland , 1984].…”

Section: Introductionmentioning

confidence: 71%

“…While we anticipate the development of charge centers within the devil, we also expect that the overall charge in the devil to have a net value of zero, making n L Q L = −n S Q S and where Δv = v L − v S < 0 is the differential velocity between large and small grains. A similar assumption is applied in thunderstorm charging [ Mathpal et al , 1980]. While charge neutrality is applied and the system is treated as closed, in reality some charge may escape, and a discussion of the relaxing of charge neutrality is presented in the conclusions.…”

Section: Electrostatic Modelmentioning

confidence: 99%

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Integration of electrostatic and fluid dynamics within a dust devil

Farrell¹,

Rennó²,

Delory³

et al. 2006

J. Geophys. Res.

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[1] In this study we derive an analytical expression to describe the electrostatic field in a dust cloud with grain trajectories defined by fluid dynamics and grain charging via contact electrification. In order to solve for the electric field, we merge the fluid dynamic-driven grain motion directly into the basic electrostatic formalism to end up with an electric field dependent on meteorological variables within the dust cloud. We find that the E field is driven by two processes: the currents associated with the charging grains and the increasing velocity difference of varying-sized grains at early times. The resulting processes give rise to an exponentially growing electric field, which for Mars applications, quickly approaches breakdown values. Variations in the growth of the electric field are found with varying grains sizes and varying ambient atmospheric conductivity.

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Section: Introductionmentioning

confidence: 71%

Section: Electrostatic Modelmentioning

confidence: 99%

Integration of electrostatic and fluid dynamics within a dust devil

Farrell¹,

Rennó²,

Delory³

et al. 2006

J. Geophys. Res.

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show abstract

“…Placing into and time‐differentiating yields

where the prime indicates the time‐differentiation operation, d/dt. At this point, the expression is similar to Equation (A10) of Mathpal et al [1980] that describes the induction electrification process between graupel and water/ice in terrestrial thunderstorms. We now deviate from that work in two key ways: First, a different driving function Q L ′ will be implemented based on triboelectric processes [ Melnik and Parrot , 1998; Desch and Cuzzi , 2000] instead of induction process, and the atmospheric conductivity, σ, will be considered for both Earth and Mars.…”

Section: Electrostatic Systemmentioning

confidence: 94%

A simple electrodynamic model of a dust devil

Farrell

Delory

Cummer

et al. 2003

Geophysical Research Letters

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[1] We present an electrodynamic model of a dust devil applying a similar methodology as performed previously for charging in terrestrial thunderstorms. While thunderstorm processes focus on inductive charging between large graupel and smaller ice and water droplets, we tailor the model to focus on the electric charge transfer between dust grains of different sizes and compositions. We specifically compare and contrast the triboelectric dust charging processes presented previously in Melnik and Parrot [1998] and Desch and Cuzzi [2000] in the development of macroscopic dust devil electric fields. We find that large vertical E-fields ($20 kV/m) can develop in the devil. INDEX TERMS: 3304

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“…They created an electrodynamic model of a dust devil by applying the methodology used for modelling terrestrial thunderstorms, e.g. see Mathpal et al (1980) to the induction electrification process between graupel and water/ice in terrestrial thunderstorms. The time derivative of the electric field, E, is related to rate of charging on the larger grains, Q L , by…”

Section: Applications Of the Charge Exchange Mechanism To Dust Devilsmentioning

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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Precipitation‐powered mechanisms of cloud electrification

Cited by 16 publications

References 74 publications

Integration of electrostatic and fluid dynamics within a dust devil

Integration of electrostatic and fluid dynamics within a dust devil

A simple electrodynamic model of a dust devil

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

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