Dust devil properties

Crozier, W. D.

doi:10.1029/jc075i024p04583

Cited by 40 publications

(22 citation statements)

References 4 publications

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“…It was found that the electric field was upward pointing in dust devils. Freier's findings were later confirmed by Crozier (1964Crozier ( , 1970. These pioneering measurements of dust devil electric fields are consistent with results of more recent measurements Fig.…”

Section: Surface Measurementssupporting

confidence: 78%

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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Section: Surface Measurementssupporting

confidence: 78%

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

et al. 2016

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“…The time evolution of space charge density is very similar to the initial accumulation of the thunderstorm space charge in the QE heating model before a conventional breakdown is reached [Pasko et al, 1997]. This maximum electric field for a typical terrestrial dust devil is difficult to compare with experimental measurements, all of which have strongly saturated at a few kV/m [Freier, 1960;Crozier, 1964Crozier, , 1970Farrell et al, 2004], but the predicted value of 150 kV/m is not inconsistent with these measurements. Very recently, Jackson and Farrell (submitted man- Melnik and Parrot [1998], the dissipation of dust grain charge due to atmospheric conductivity is fully considered in our FE simulation.…”

Section: Quasi-electrostatic Dust Devil Simulationsmentioning

confidence: 73%

“…The modeled terrestrial dust devil electric field reaches breakdown value (3 MV/m) in less than 5 min. This model predicts unlimited growth of dust devil electric fields that are not consistent with past observations of terrestrial dust devils, where only a maximum electric field of a few kV/m has been observed [Crozier, 1970;Farrell et al, 2004]. Most recently, Jackson and Farrell (submitted manuscript, 2005) measured near 120 kV/m QE fields of dust devils with a carefully calibrated electrometer.…”

Section: Introductionmentioning

confidence: 91%

“…[Crozier, 1964[Crozier, , 1970Farrell et al, 2004]. To study the evolution of field and charge in a dust devil and how the tribocharging process is saturated by atmospheric conductivity that controls the exponentially growth of the maximum in-devil electric field, we perform following simulations of quasi-static electrification with our finite element model for Martian and terrestrial dust devils of different size, conductivity, and time rate of charging.…”

Section: Quasi-electrostatic Dust Devil Simulationsmentioning

confidence: 99%

“…[3] Past in situ measurements suggest that large electric fields (bigger than 4 kV/m where many instruments have saturated and has been recently measured to be near 120 kV/m) exist in terrestrial dust devils [Crozier, 1970;Farrell et al, 2004] (see also T. L. Jackson and W. M. Farrell, Electrostatic fields in dust devils: An analog to Mars, submitted to IEEE Transactions on Geoscience Remote Sensing, 2005) (hereinafter referred to as Jackson and Farrell, submitted manuscript, 2005). Recent numerical and analytical studies show that the micro-electro-aerodynamical system of a dust devil is an efficient giant electric generator that may trigger Martian electrical discharges and radio emissions Parrot, 1998, 1999;Farrell et al, , 2003.…”

Section: Introductionmentioning

confidence: 99%

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Quasi‐electrostatic field analysis and simulation of Martian and terrestrial dust devils

2006

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[1] Recent experimental and modeling studies show that large quasi-static electric fields (2-20 kV/m) can be developed in a Martian or terrestrial dust devil as a result of contact electrification and charge separation of dust grains with different sizes and compositions. Electric discharging occurs when the maximum electric field reaches breakdown values ($20 kV/m on Mars and $3 MV/m on Earth, at surface altitudes). We derive a maximum electric field in a dust devil and develop a two-dimensional (2-D) cylindrically symmetric finite element model for Martian and terrestrial dust devil simulations. Unlike previous models with unlimited field growth, the tribocharging process and the time evolution of the dust devil electric field are self-consistently limited in our model and the saturated maximum electric fields in our simulations are comparable to past measurements. We study the saturated maximum electric fields for dust storms of different size, atmosphere conductivity and time rate of tribocharging. We also discuss the 2-D cylindrical field structures surrounding a dust devil and the conductivity gradient effect to the field growth of large Martian dust storms.

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Dust devil dynamics

et al. 2016

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A self‐consistent hydrodynamic model for the solar heating‐driven onset of a dust devil vortex is derived and analyzed. The toroidal flows and vertical velocity fields are driven by an instability that arises from the inversion of the mass density stratification produced by solar heating of the sandy surface soil. The nonlinear dynamics in the primary temperature gradient‐driven vertical airflows drives a secondary toroidal vortex flow through a parametric interaction in the nonlinear structures. While an external tangential shear flow may initiate energy transfer to the toroidal vortex flow, the nonlinear interactions dominate the transfer of vertical‐radial flows into a fast toroidal flow. This secondary flow has a vertical vorticity, while the primary thermal gradient‐driven flow produces the toroidal vorticity. Simulations for the complex nonlinear structure are carried out with the passive convection of sand as test particles. Triboelectric charging modeling of the dust is used to estimate the charging of the sand particles. Parameters for a Dust Devil laboratory experiment are proposed considering various working gases and dust particle parameters. The nonlinear dynamics of the toroidal flow driven by the temperature gradient is of generic interest for both neutral gases and plasmas.

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Dust devil properties

Abstract: Measurements of electric moment are reported for seventeen New Mexico dust devils. Estimates of charge and charge density were made for eight of these; charge densities appear generally to be of the order of 106 elementary charges cm−3. Ground speeds ranged from 5–11 m sec−1.

Cited by 40 publications

References 4 publications

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

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

Quasi‐electrostatic field analysis and simulation of Martian and terrestrial dust devils

Dust devil dynamics

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