嫦娥四号着陆区织女陨坑电场环境数值模拟

由于太阳紫外、X射线和太阳风粒子作用，近月表形成尘埃等离子体环境，而月表陨坑地形使得这种尘埃等离子体环境更为复杂.本文以位于嫦娥四号着陆区的织女陨坑为研究对象，基于高程数据构造了该陨坑的三维模型.根据太阳-月球关系和陨坑地理坐标信息，计算了陨坑白天任意时刻的有效太阳辐照度分布，探讨了不同时刻陨坑内外的光照面积占比，得到陨坑随地方时而发生的遮蔽效应特征.同时，基于月表充电方程计算了织女陨坑在不同地方时条件下的平衡表面电势、德拜鞘高度和电场强度分布，发现陨坑自身遮蔽效应对坑内电场环境影响十分明显.以坑底中心为例，讨论了地方时和纬度对类织女陨坑的平衡表面电势、德拜鞘高度及电场强度的影响，结果表明三者变化特征均以正午时刻及赤道为界呈对称分布，越接近12：00LT或者越接近赤道，坑底中心的平衡表面电势和电场强度越高，德拜鞘高度越低.

Electric Fields Distribution of Zhinyu Crater in Chang’E-4 Landing Area

Solar radiation and solar wind create a complex dust-plasma environment in lunar crater.Based on the elevation data obtained from the Lunar Orbiter Laser Altimeter(LOLA)onboard Lunar Reconnaissance Orbiter(LRO),we constructed a three-dimensional model of Zhinyu crater which located in the Chang’E-4 landing area,and then calculated the effective solar irradiance and the percentage of illuminated area at different local time in the lunar daytime.The results show that the crater self-shading effect plays an important role in crater illumination conditions,and the percentage of illuminated area reaches 100%only during 10:30 LT-13:30 LT.In acldition,we calculated the distributions of equilibrium surface potential,Debye length and electric field at different local time,which were found to be highly dependent on the crater self-shading effect.Finally,we discussed the relationship of equilibrium surface potential,Debye length and electric field at the bottom of Zhinyulike crater with local time and latitude.The results show that the distributions of equilibrium surface potential,Debye length and electric field are symmetric along the time of 12:00 LT and lunar equator.These values almost remain unchanged on the shadow areas and change slightly on the sunlit areas,but change dramatically at the dead zone.