Experimental Demonstration and Quantification of Electrostatic Lofting of Dust Clumps

Abstract

Electrostatic lofting of individual regolith grains on the Moon and asteroids has been investigated extensively. However, motion of clumps has been mentioned only anecdotally. For the first time, we electrostatically lofted clumps of 200-300 micrometer zirconia-silica microspheres in vacuum and quantitatively analyzed their trajectories. The microspheres were charged by an emissive filament. A biased plate produced an electric field of 870 kV/m that attracted sufficiently charged clumps from the surface. A high-speed camera imaged the lofted clumps at 945 fps in order to obtain their size and centroid positions over time. Using the centroids from the initial clump detachment, we numerically calculated an initial acceleration to solve for the cohesion that had been restraining the clump. These experimental results show that the detachment of clumps of particles are a non-negligible portion of the lofted object population for cohesive powders. Thus, if electrostatic lofting occurs on small airless bodies, we will likely see clumps lofted.