Theoretical analysis of the electric potential and the electrostatic dust transport around the Shackleton crater in the Lunar south pole region

摘要

In recent years,the Lunar south pole region(SPR)has become the focus of future explorations due to its special illumination condition and the possible water ice in permanently shadowed craters around it.The Shackleton crater locates almost exactly at the Moon’s south pole and has become the hottest destination for several landing missions,including the Chang’E-7 mission.However,people still know little about the electric potential and the dust environment around this crater.In this paper,we develop an analytical model to study the surface potential and the electrostatic dust transport around the crater.It is found that the crater’s floor can be negatively charged due to the topographic shielding,and the surface potential is as low as-175 V on the leeward crater wall.Accordingly,a large number of charged dust grains can be emitted from the leeward crater wall,with a maximum height of about 10 km and a horizontal distance of about 40 km,which brings a local dust cloud around the crater.Both the topographic shielding and the local dust cloud are qualitatively verified by a numerical simulation,in which a typical dust density of 10^(4)-10^(5)m^(-3)is found near the crater.Our results are important to the environmental assessment for future explorations near the crater.Furthermore,the results are helpful to understand the surface charging and the electrostatic dust transport on the other airless bodies.