【作者】 李德；

【导师】 曹勇；

【作者基本信息】 哈尔滨工业大学 ， 机械工程（专业学位）， 2021， 硕士

【摘要】 登月作为人类漫长而艰巨的太空旅程的第一步,是人类迈向太空的重要基点,但阻碍人类探月进程的却是月球上随处可见的尘埃粒子——月尘。由于月尘带有静电电荷,它可以黏附在其接触的任何表面上,月尘有很强的腐蚀性,能够磨损宇航服和其附着的电子设备,并导致关键机构卡死,损坏控制系统等危害。目前主要认为静电迁移是月尘的主要运动机制,在月球四周太阳风等离子体粒子的作用下,月球的各个区域,特别在光照与阴影的分界线附近会形成复杂的电场结构,但目前对交界区域的鞘层特性的探索还存在不足。因此对明暗交界区域中的等离子体环境及其鞘层结构的研究对月尘颗粒的迁移机理起着至关重要的作用。本文根据浸入式有限元与质点网格法(IFE-PIC)理论建立了明暗交界区域的鞘层模拟程序,模拟了月表晨昏线明暗交界区域电场环境。模拟结果表明,月表电势从非光照区域的低电势过渡到光照区域的高电势,在交界线附近的电场强度远大于其他区域的电场强度。此外发现了明暗交界区域的鞘层振荡现象,探究了明暗交界区域的鞘层振荡特性,结果表明明暗交界区域鞘层的振荡周期与该环境下的等离子体振荡周期基本相同,且光照区域鞘层振荡幅度大于非光照区域的振荡幅度,随着与交界线距离的增大,鞘层的振荡幅度逐渐增大。通过鞘层模拟程序探讨了太阳风环境参数对明暗交界区域鞘层结构的影响,由于等离子体密度、电子与光电子温度、光电子密度等会影响鞘层中的电流源,会导致明暗交界线两侧表面电荷量差异的变化,并对交界线附近的鞘层结构造成影响。最后根据月尘的充放电模型以及动力学模型,对晨昏线明暗交界区域中的月尘静电迁移运动进行了仿真模拟,探讨了带电月尘在明暗交界区域中的静电浮扬特性,研究结果表明在晨昏线附近的在交界线附近的带电月尘粒径越小,浮扬高度越高,在交界线附近的部分区域,受到明暗交界处水平电场的影响,不同月尘粒径的水平迁移距离相差不大。更多还原

【Abstract】 As the first step of mankind’s long and arduous space journey,the moon is an important starting point for mankind to move into space,but what hinders mankind is the dust particles that can be seen everywhere on the moon.Because moondust is electrostatically charged,it can stick to any surface it touches.Moondust is corrosive and can wear the spacesuit and electronic equipment,to cause critical mechanisms to jam and damage the control system.At present,it is mainly believed that electrostatic migration is the primary movement mechanism of moondust.Due to the special plasma environment around the moon,a complicated electric field structure will be formed on the lunar surface,especially in the lunar terminator region.However,there is a lack of research on the characteristics of the sheath in the lunar terminator region.Therefore,the study of the plasma environment and its sheath structure in the lunar terminator region plays a vital role in the migration mechanism of moondust particles.Based on the theory of immersed finite element and particle in cell,a sheath simulation program for the terminator region is established,the electric field environment in the terminator region of the lunar surface is simulated.The simulation results show that the electric potential of the lunar surface transitions from low electric potential in a non-illuminated area to high electric potential in an illuminated area,and the electric field intensity near the boundary line is much greater than that in other areas.The sheath oscillation phenomenon in terminator region is discovered,and the sheath oscillation characteristics in this area are analyzed.The results show that the oscillation frequency of the sheath in terminator region is the same as the plasma oscillation frequency,and the sheath oscillation amplitude in the illuminated area is greater than that in the non-illuminated area.The influence of the solar wind environment parameters on the sheath structure of the terminator region is discussed through the sheath simulation program.Plasma density,electron and photoelectron temperature,photoelectron density will affect the current source in the sheath,which will cause the difference in surface charge on both sides of the terminator region,and affect the sheath structure near the junction.Finally,according to the charging and discharging model of the moondust and the dynamic model,the electrostatic migration of the moondust in the terminator region was simulated.The electrostatic floating characteristics of the charged moondust in the terminator region were discussed.The research results show that the smaller the particle size of the charged moondust near the junction,the higher the flying height,but the horizontal migration distance of different moondust size is not much different under the influence of the horizontal electric field at the junction.更多还原