Dust escape from Mars

Martian dust can be lifted to about 100 kilometres by known processes such as dust storms (e.g. Heavens et al, J. Atmos. Sci. 76, 2019). Dust has been observed at higher altitudes, but this is attributed to capture of interplanetary dust (Andersson et al, Science 250, 2015).

During its flight from Earth to Jupiter, a star camera on the Juno spacecraft observed dust in the size range of 1-100 um, contributing to the Zodiacal light and sharing orbital elements with Mars (Jørgensen et al, JGR: Planets 126, 2020). The origin of this dust was speculated to be Mars itself but a mechanism that allows the dust to reach escape velocity (~5 km/s) has not yet been identified. While dust can theoretically be lofted to hundreds of kilometres by electric forces on, for instance, the Moon (Wang et al, Planet. Space Sci. 184, 2020), the Martian atmosphere (thin as it is) makes this more difficult.

In this work we investigate the possibility of dust escaping Mars by electric forces. In order to reach the escape velocity a dust particle must overcome the forces of gravity and atmospheric drag. Beyond altitudes reached by meteorological phenomena, only electric forces can accelerate the particles. Recently observations by the Perseverance rover (Chide et al, Nature 647, 2025) showed discharges during dust events, indicating that the Martian atmosphere can have breakdown fields (about 15 kV/m at ground level).

In our model a dust particle of a prescribed size, charge, and updraft velocity is released at a given altitude into an atmosphere with an altitude dependent electric field. The resulting electric, drag, and gravity forces are calculated to find the particle’s velocity and altitude as a function of time. We test limit cases of electric charge and fields for relevant particle sizes to see what velocity is reached and how far a particle can be lifted.