A laboratory model of the lunar surface potential near boundaries between sunlit and shadowed regions

Abstract

There is a convincing body of evidence about the mobilization and transport of small dust grains on the lunar surface, and in general, on the surfaces of airless bodies in the solar system. Surfaces in space exposed to plasmas and UV radiation will become charged, and develop a sheath region with an electric field normal to the surface. Typically, this electric field is on the order of a few V/m, too small to lift‐off micron sized grains with an expected charge of a single electron on the lunar surface, for example. Much higher electric fields can be generated due to differential UV charging between neighboring lit and dark surface elements, a common situation during sunset or sunrise. Here we report on a series of experiments to investigate differential photoelectron charging, and the so‐called ‘super‐charging’ effect, related to the moving boundaries between illuminated and dark surfaces.