The lunar dust pendulum

Dependence of lunar surface charging on solar wind plasma conditions and solar irradiation

“…However, modeling done by Hartzell and Scheeres (2011) suggests that surface electric fields have to be greater than ~5 × 10 5 V m í1 in order for electrostatic forces to be able to overcome gravity, and more importantly, inter-grain cohesive forces. Therefore, the E S values predicted here appear to be orders-of-magnitude too weak to initiate electrostatic ejection of charged dust grains; although they are typically strong enough to have a significant influence 765 on the trajectories of some charged dust grains already in the exosphere, and could result in some form of either levitation, lofting or oscillatory motion (e.g., Colwell et al, 2007;Stubbs et al, 2006;Collier et al, 2013). It remains unclear how such dust grains from the regolith enter the exosphere, but it has been speculated that they could be ejected from the surface by a saltationlike cascade process initiated by meteoritic impacts (Glenar et al, 2011).…”

“…The finest component of the lunar dust (< 10 ȝm) is most susceptible to electrostatic forces (Colwell et al, 2007). The two modes of electrostatic transport of most interest are anticipated to be levitation (Nitter and Havnes, 1992;Nitter et al, 1998;Sickafoose 70 et al, 2002;Poppe and Horanyi, 2010;Poppe et al, 2012;Collier et al, 2013) and lofting (Stubbs et al, 2006;2007c;Farrell et al, 2007;. The most compelling evidence for the transport of charged dust on the Moon comes from the Lunar Ejecta and Meteorite (LEAM) experiment deployed on the surface by the Apollo 17 mission, which appeared to detect relatively slow-moving (~100 m s -1 ), highly-charged dust grains of lunar origin, particularly near 75 lunar sunrise and sunset; see Berg et al (1976), Colwell et al (2007), and references therein, as well as O'Brien (2011) for an alternative interpretation of the LEAM measurements.…”

Search for a high‐altitude lunar dust exosphere using Clementine navigational star tracker measurements

“…Proposed mechanisms for the generation of the putative submicron exospheric dust population typically involve either electrostatic forces and/or meteoritic impacts. Since both the surface of the Moon and dust in the lunar exosphere become electrostatically charged by their interaction with the space environment [e.g., Whipple, 1981;Stubbs et al, 2014a], dust grains could be transported by the electrostatic repulsion from the like-charged surface [Rennilson and Criswell, 1974;Poppe and Horányi, 2010;Collier et al, 2013]. Despite the fact that electrostatic forces appear to be insufficient to eject dust grains from the surface due to the dominance of cohesive forces between neighboring grains [Marshall et al, 2011], it is possible that electrostatic forces control the transport of grains once they are ejected by some other mechanism.…”

Simulations on Levitation and Spatial Distribution of Charged Dust on the Moon Surface

“…The Lunar Atmosphere and Dust Environment Explorer has observed some strong dust signals over several impact craters near the terminator, and calculations have revealed that the potential on the leeward side of the craters can be less than −700 V. Such crater potential may generate a strong enough electrostatic field to horizontally transport dust grains of 0.1 μm to about 200-300 km and vertically levitate those grains to an altitude of more than 200 km (Xie et al 2020). Collier et al (2013) and Xie et al (2020) also demonstrate that local topography (e.g., craters) has a dramatic effect on lunar surface charging and dust levitation. Lunar surface potential distribution and the motions of single dust grains in the lunar sheath have been studied previously.…”