Plasma Particle Simulations of Wake Formation behind a Spacecraft with Thin Wire Booms
Plasma Particle Simulations of Wake Formation behind a Spacecraft with Thin Wire Booms
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带有细线吊杆的航天器后面尾流形成的等离子体粒子模拟
DOI：
10.1002/jgra.50543
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Hiroshi Nakashima
中科院分区：
文献类型：
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作者：
Yohei Miyake;Chris M. Cully;Hideyuki Usui;Hiroshi Nakashima
安装在科学航天器上的双探头电场传感器通常使用半径比典型的磁层等离子体德拜长度(毫米比几十米)小得多的导线吊杆。然而，在极冠和极叶区域可以看到的稀薄和冷流等离子体中，在航天器电接地的导线吊杆由于光电子发射而具有高正势，并可以强烈散射接近的离子。因此，导线吊杆的存在进一步增强了航天器后面形成的静电尾迹。我们通过执行等离子体细胞内粒子(PIC)模拟来再现集群卫星的这一过程，该模拟同时包括航天器机身和导线吊杆的影响。模拟结果表明，当航天器电势为几十伏时，集束电场与波(EFW)仪器的有效吊杆厚度从实际直径(2.2 mm)放大到几米。这种轰击使尾迹电场强度增加了1.5-2倍，取决于航天器的位势，并在解释原位星团EFW数据显示约10 mV/m幅度的正弦杂散电场方面发挥了主要作用。通过比较使用和不使用钢丝吊杆的PIC模拟，以及检查不同航天器潜力的尾迹形成，对吊杆效应进行了量化。
Double‐probe electric field sensors installed on scientific spacecraft are often deployed using wire booms with radii much less than typical Debye lengths of magnetospheric plasmas (millimeters compared to tens of meters). However, in tenuous and cold‐streaming plasmas seen in the polar cap and lobe regions, the wire booms, electrically grounded at the spacecraft, have a high positive potential due to photoelectron emission and can strongly scatter approaching ions. Consequently, an electrostatic wake formed behind the spacecraft is further enhanced by the presence of the wire booms. We reproduce this process for the case of the Cluster satellite by performing plasma particle‐in‐cell (PIC) simulations, which include the effects of both the spacecraft body and the wire booms in a simultaneous manner. The simulations reveal that the effective thickness of the booms for the Cluster Electric Field and Wave (EFW) instrument is magnified from its real diameter (2.2mm) to several meters, when the spacecraft potential is at tens of volts. Such booms enhance the wake electric field magnitude by a factor of 1.5–2 depending on the spacecraft potential and play a principal role in explaining the in situ Cluster EFW data showing sinusoidal spurious electric fields with about 10mV/m amplitude. The boom effects are quantified by comparing PIC simulations with and without wire booms and also by examining the wake formation for various spacecraft potentials.