Effect of work function on dust charging and dynamics on airless celestial body

Abstract

Charged dust on the surface of airless celestial bodies, such as the Moon and asteroids, poses a threat to space missions. Further research into charged dust is essential for the success of future space missions. In this study, we investigated the charging and dynamics of dust particles by examining different work functions. By integrating the photoelectron energy distribution function over four different work functions, we evaluated the variations in photoelectron density within the dust charge environment caused by changes in the work function. Using the photoelectron density corresponding to each work function, we solved the dust charging and dynamic equations for each type of dust under two different gravitational acceleration values. The results revealed that dust with a lower work function reaches higher equilibrium states, though it takes longer to achieve these states. These equilibrium states include charging currents, charge numbers, and levitation heights. The results also showed that equilibrium states have an inverse relationship with the work functions of dust particles as the solar zenith angle (SZA) varies from 0°to 90°, displaying consistent trends under different gravitational accelerations. Additionally, we found that dust particles could not levitate stably at a critical SZA, with this critical SZA following the same pattern as that of the work function. These findings could inform the design of dust mitigation strategies for future space missions, enhancing the safety and longevity of spacecraft operating on airless celestial bodies.