Numerical simulations of a dust devil and the electric field in it

Abstract

Dust devils are very common meteorological phenomena on the Earth as well as on Mars. They are an abbreviated wind‐sand conveyance system. The moving particles in dust devils may become electrically charged, to the point of arcing to spacesuit or vehicle, and creating electromagnetic interference. In this paper a numerical model, which takes into consideration the effect of thermal flux from the surface to the atmospheric boundary layer, is employed to simulate a dust devil and to obtain its fine structure and its development. Then, on the basis of Coulomb's law, the electric field and its distribution in a dust devil are numerically simulated in this paper. The numerical results are consistent with theoretical models for dust devils. That is, the formation mechanisms of a dust devil can be explained with the theory of thermal convection. The numerical results also show that at the beginning stage of the evolution of a dust devil the electric field strengthens with time, but after 80 s the electric field changes little and the electric field has trended to a dynamic stabilization. The electric field in a dust devil has a maximum value at a certain height; the electric field will be increscent below this height and decrescent above this height at the interior of a dust devil.