等离子体鞘层效应对磁层探测电场仪设计的影响

在空间环境探测中，卫星与等离子体的相互作用会改变背景环境的粒子和电位的分布，从而影响探测器对空间电场的测量.为了给磁层卫星电场探测仪器的研制和设计提供参考，本文以中国未来的磁层电离层探测为背景，针对不同轨道高度的等离子体环境，利用SPIS（Spacecraft Plasma Interaction Software）模拟了卫星平台和探针与等离子体的相互作用，从而得到了不同环境下卫星周围等离子体鞘层的厚度，以及探针电位与电流的对应关系.模拟结果表明:由于光电子和二次电子的影响，卫星鞘层的厚度小于等离子体的德拜半径，且温度越高其偏差越大；模拟得到的探针表面电流与电位的关系表明，施加偏置电流的探针可明显提高对电流扰动的抗干扰能力.此外，估计了不同轨道高度上探针处于最佳工作点时应施加偏置电流的大小. 

Effect of Plasma Sheath on the Design of Electric Field Instrument Detecting Magnetosheath

The distribution of plasma potential and density around spacecraft is affected by the coupling of spacecraft and plasma, resulting in disturbing the detection of space electric field. In this paper, Spacecraft Plasma Interaction Software (SPIS for short) is used to provide a reference to design the electric field instrument detecting magnetosheath on future missions. The interaction of plasma with the spacecraft platform and the probe is simulated to investigate the thickness of plasma sheath and the relationship between current and voltage drop under different plasma conditions. Our results indicate that the thickness of plasma sheath covered spacecraft is smaller than the Debye radius, and this difference is larger at higher temperature conditions caused by photoelectrons and secondary electrons. Moreover, the current collected by the probe at a different voltage drop is also simulated. The simulated results show that the influence of current disturbance on measuring potential can be reduced by the probe with a bias current. Furthermore, the estimated optimum bias current is also listed corresponding to the detected region.