Laboratory measurements of size distribution of electrostatically lofted dust

Electrostatic dust lofting has been suggested to explain a number of unresolved phenomena on airless planetary bodies such as the lunar horizon glow, the dust ponds on asteroid Eros, and the radial `spokes' in Saturn's rings. In this paper we report laboratory measurements of the size distribution of lofted dust particles in the range of 1 to 40 mu m in diameter. It is shown that the population of lofted dust increases with a decrease in dust size (i.e., smaller sized dust is easier to be lofted), which is in agreement with the theoretical expectation derived from the patched charge model (Wang et al., 2016a). Additionally, initial launch velocities are derived from transport distances of lofted particles following ballistic trajectories. It is shown that the initial velocity of lofted particles is inversely proportional to their size, in agreement with an earlier work that used a different measurement method (Carroll et al., 2020).