近年来,越来越多的观测结果均显示月球上存在水.本文通过运用Monte-Carlo方法及基于能量守恒的有心力场中粒子轨道算法对水分子在近月表的输运过程进行建模,得到了水分子在近月表分布随时间演化的图像.模拟结果显示,分布在高纬地区的水分子较同经度的中低纬地区要多,这与目前探测得到的结论是一致的.同时,对最终进入永久阴影区的水分子的百分比进行了统计,在光解离常数为6.4×104s的情况下,有大约4.12％的水分子会被永久阴影区存储下来,这个比例与前人估算结果相吻合.%Recent observations confirmed that the lunar surface is hydrated.Former Monte-Carlo simulation has estimated the potential amount of water in the polar regions,whereas the distribution character of water in the lunar space environment remains unknown.By applying a combined model of Monte-Carlo method and a central force algorithm based on energy conservation,this paper has investigated the character of the water molecular density distribution in the Moon's exosphere and the evolution of global surficial density,using solar wind proton as the water origin.The results show about 4.12％ of all water molecules travel down to the Permanently Shadowed Regions (PSR) and become stable,under the circumstance that the timescale for photo-dissociation is 64 000 seconds for water,which agrees with the previous simulation.It also indicates there are larger abundances of water in higher latitude regions.
展开▼
