Multiscale Modeling of Dust Charging in Simulated Lunar Environment Conditions

Abstract

A key aspect of dust adhesion to space equipment is the accumulation of charge under the space plasma environment. Recent models and experiments show possible negative charging of dust grains under VUV illumination. Macroscopic potential measurements conducted during a test campaign show that both positive and negative average charging can be reached under VUV irradiation pending on vacuum chamber configuration, suggesting that both situations can exist at lunar surface. Simulations of dust charging at microscopic scale are conducted with the SPIS software to evaluate electrical charge and electric field amplifications induced by the granular structure of the lunar regolith. A multi-layer pile of dust is modelled under lunar conditions. Grains from the first two layers tend to microscopically acquire both negative and positive charge patches when illuminated with a 45° VUV incidence angle, this differential charging being less pronounced under normal incidence angle. It is also found that dust deeply buried in the lunar soil may charge more negative due to the collection of environmental electron only. This effect is thought to reinforce the grain supercharging model presented by other authors. We show however that such charge development may be limited by electrical conduction pending on dust electrical properties.Index Terms-dust lofting, lunar dust, electrical charge.

Charging and Levitation of Particles Using UV Irradiation and Electric Field

“…UST particles on the dayside surface of the moon and on asteroids without atmosphere are exposed to solar radiation. The particles are charged by the photoelectric effect due to ultraviolet (UV) irradiation [1][2][3] and easily adhere to devices and spacesuits, resulting in damage to equipment and human health. Therefore, dust removal technologies using electric fields, such as electrodynamic dust shields, have been developed [4][5][6].…”

Aerospace Environmental Challenges for Electrical Insulation and Recent Developments for Electrified Aircraft

“…During the lunar day cycle the regolith, through photoelectric emissions, charges and ionizes regolith particles. The particles on the lunar day side are positively charged, due to the photoelectron emissions, while particles on the night side are negatively charged [39][40][41]. Even more interesting, is the voltage potential (V) on the lunar surface that can depend on different factors, such as location on the Moon.…”

Effective Use of External Electric Field for Charging and Levitation of Particles Under UV Irradiation

“…Particles can be charged via photoemission induced by ultraviolet (UV) irradiation, which is more efficient than the common techniques of ion charging because it does not require the addition of extra ions or electrons [11]- [14]. When the surface of the particle layers is irradiated with UV light, the particles are positively charged by the emission of photoelectrons.…”