The role of cohesive forces in particle launching on the Moon and asteroids

The movement of small dust particles due to electrostatic forces, seismic activity and micrometeoroid bombardment has been hypothesized to occur on the Moon and asteroids. There currently exists significant uncertainty in the method of launching these small dust particles, which in turn makes the selection of accurate initial conditions for numerical simulations difficult. We evaluate the electric field strength required to launch small particles given surface gravitation, cohesion and seismic shaking. We find that the electric field strength required for dust particle launching is dominated by the cohesive force for micron-sized dust particles. There exists an intermediate dust particle size that requires the least electric field strength to launch. We see that the inclusion of the cohesive force significantly influences our understanding of dust lofting.

► Modeled electrostatic force required to loft dust particles on Moon and asteroids.
► Including cohesion significantly increases the electrostatic force required.
► Charge amplification beyond Gauss' law prediction is required to loft particles.
► Particles requiring smallest electric field for lofting may be larger than 10μm.