尾迹对卫星周围等离子体扰动特性分析

Investigation of the Influence of Wake Effect on Plasma Sheath

卫星充电和尾迹效应会对周围的等离子体造成扰动,进而影响星上电磁和等离子测量载荷的测量精度。利用卫星与等离子体相互作用模拟软件SPIS,并采用DEMETER卫星的一组在轨测试的等离子参数,采用粒子分室法模拟了低轨道卫星的尾迹效应特性。结果显示,卫星的表面充电电位为-0.72V,负的充电电位一定程度上减小了尾迹效应的影响,尾迹效应对等离子体的扰动在尾迹一侧约为2.5m,离子撞击侧约为0.7m,其余两个侧面约为1.1m,即等离子鞘层呈桃形分布,且在尾迹区存在离子浓度为零的空白区和浓度较小的稀薄区,而在尾迹区也是电子浓度的稀薄区,但不存在电子浓度为零的空白区。

The wake effect can disturb the plasma around the spacecraft ; and it can influence the detection precision of elec- tromagnetism and plasma payloads. In order to investigate the wake characteristic, we use the SPIS （Spacecraft Plasma Interaction System） software and the Particle in Cell method to investigate the wake effect. The satellite mode and plasma parameters were got from the DEMETER satellite. The simulation results show that the satellite charging potential is - 0.72 V and the plasma around the satellite is signit^canfly disturbed by the wake effect. The sheath is like a peach in shape, in the wake side about 2.5 m, ram side about 0.7m and the other two sides about 1.1 m. And in the wake region, the electrons that initially enter the wake build up a space charge that repels all other electrons, so the wake can be considered essentially also devoid of electrons.