旋转小行星上陨石坑表面充电的三维模拟
Three-dimensional Simulation of Surface Charging in Meteorite Craters on Rotating Asteroids
AI总结：
本文利用神经网络与有限元方法模拟旋转小行星表面陨石坑的充电特性，揭示了纬度、深宽比和太阳风暴对坑底电位的不同影响，为未来小行星安全着陆与探测提供依据。
摘要：
小行星表面的陨石坑会阻碍太阳风的水平流动，形成等离子体尾流，从而调制远下游的粒子通量和静电环境。本研究基于神经网络和有限元方法，对具有非平凡地形的小行星表面充电特性进行了模拟。研究中考虑了陨石坑的位置、尺寸和深宽比等关键因素。在正常条件下，随着陨石坑纬度的增加，其底部在一个自转周期内的电位变化逐渐趋于平缓，当陨石坑接近极区时，电位最终稳定在约-3V左右，仅伴有微小波动。对于深宽比大于0.5的陨石坑，由于电子的发散运动以及离子轨迹偏转较小，在太阳风平行入射和垂直入射两种情况下观察到完全不同的充电结果：随着深宽比的增大，陨石坑底部周围的电位在平行入射时降低，而在垂直入射时升高。虽然表面电位对陨石坑尺寸的变化似乎不敏感，但仅在太阳风暴期间，大尺度陨石坑（例如直径为800m的陨石坑）的底部电位相比50m的小陨石坑出现了9.13V的下降。对局部等离子体流场和小行星表面充电现象的研究，对未来安全着陆和探测任务都具有重要影响。
英文摘要：
Meteorite craters on the asteroid surface obstruct the horizontal flow of solar wind, forming a plasma wake that modulates the particle fluxes and the electrostatic environment far downstream. In this study, surface charging properties of asteroids with nontrivial terrain are simulated based on neural network and the finite element method. Key factors such as the location, size and depth-to-width ratio of craters are all considered. Under normal conditions, as the latitude of the crater increases, the potential variation at its floor during a rotation gradually becomes smoother, finally stabilizing around -3V with minor fluctuations as the crater approaches the poles. For craters with a depth-to-width ratio greater than 0.5, because of the diverging motions of electrons and the less deflected trajectories of ions, completely different charging results are observed under parallel and perpendicular solar wind incidence, the potential around the crater floor decreases and increases with the rising depth-to-width ratio, respectively. While the surface potential appears indifferent to changes in crater size, only during solar storms, the floor of large-scale craters, such as those with a diameter of 800m, perform a 9.13V decrease in potential compared to small craters of 50m. Both studies of localized plasma flow field and the surface charging phenomenon of asteroids have substantial influence on the future safe landing and exploration missions.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
