Ranking Adhesion Forces for Charged Lunar Dust Particles on Conducting Surfaces

摘要

Both image-charge forces and surface-energy (i.e. van der Waals) interactions contributernto the adhesion of charged dust particles on conducting surfaces. In-situ lunar regolith isrncharged (positively on the sunlit side of the moon, from UV photo-ionization, andrnnegatively on the dark side, from electrons in the solar wind). Furthermore, mechanicallyrndisturbed regolith can attain a triboelectric charge which is different than its charge-staternbefore the disturbance. The expected size dependence of the charge-to-mass ratio for finernlunar particulates differs depending on which mechanism caused the charge. Based onrncurrent theories and measurements, it is expected that, as the size of dust particlesrndecreases, the adhesion forces acting on particles in contact with conducting surfaces willrnbe dominated by van der Waals' forces, or by image-charge forces, depending onrnwhether the fine particles attained their charge from solar sources (i.e., photo ionizationrnor solar wind) or from triboelectric (i.e., mechanical) means, respectively. At present wernhave insufficient information on the size dependence of charge-to-mass ratios of insitu orrnmechanically disturbed lunar regolith particles to resolve this uncertainty.