太阳风中航天器带电与尾迹效应的模拟

航天器充电和尾迹效应会对周围等离子体造成扰动，影响测量装置结果的准确性.利用SPIS （Spacecraft Plasma Interaction Software）分别模拟了航天器与太阳风的相互作用，考察了光电效应以及航天器尺度对表面充电情况和尾迹效应的影响.结果表明：太阳风环境下，等离子体密度稀薄，电子电流比光电子电流小得多，航天器表面为正电势，航天器后部有清晰的尾迹结构，尾迹带负电；光电效应可改变尾迹结构，与无光电效应相比，光电效应使得航天器尾迹尺度变大；由于太阳风定向运动动能大于航天器表面势能，航天器的尾迹结构与其几何尺寸有关，航天器尺寸越大，尾迹尺度越大.

Simulations of the Spacecraft Charging and Wake Effects in the Solar Wind

Surface charging and wake effects can disturb the plasma around the spacecraft and affect the measurements of spacecraft payloads. In this paper the Spacecraft Plasma Interaction Software (SPIS) is used to simulate the interaction between the solar wind and the spacecraft, in order to reveal the ion, electron, photoelectron, and electric potential distributions around the spacecraft. The results show that, since the plasma is tenuous, the electrons collected by the spacecraft give a much smaller current than the photoemission current, and the spacecraft could be charged to positive potential. A negatively charged wake will form downstream the spacecraft. It is demonstrated that the wake features can be altered by the photoemission. The scale of the wake can be larger due to the surface photoemission. It is also concluded that, since the bulk flow kinetic energy is much larger than the spacecraft potential energy, the size of the wake depends on the dimension of spacecraft. The wake can be substantially larger behind a larger spacecraft with the same parameters in the solar wind.