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空间等离子体在有些情形下,并非单麦克斯韦分布,而是双麦克斯韦分布。为了研究双麦克斯韦分布等离子体对航天器表面的充电效应,基于等离子体动理学理论,建立表面充电平衡方程,综合考虑双麦克斯韦分布等离子体的粒子参数、航天器的单位电容、二次电子发射及光照等因素,得出了双麦克斯韦分布等离子体对航天器表面充电电位的计算表达式,给出了表面充电电位随时间的变化规律。研究结果表明:当等离子体为双麦克斯韦分布时,航天器表面充电电位低于单麦克斯韦分布等离子体环境下的表面充电电位,单麦克斯韦分布的等离子体假设会过高估计航天器表面的充电效应;双麦克斯韦分布的第二分布函数中,对最终的表面充电平衡电位影响较大的主要是离子成分;双麦克斯韦分布等离子体的粒子数密度或温度越高,则表面充电达到平衡所需的时间越长;单位电容仅影响表面充电电位达到稳定所需的时间,对最终的充电平衡电位值影响不大。
In some cases, space plasma is not a single Maxwellian distribution, but a dual Maxwellian distribution. In order to study the charge effect of the dual Maxwell distributed plasma on the surface of the spacecraft, a surface charge equilibrium equation is established based on the plasma kinetic theory. The particle parameters of the dual Maxwell plasma, the unit capacitances of the spacecraft, the secondary electron emission Light and other factors, the calculated expression of the charge potential of the spacecraft surface by the two-Maxwell distributed plasma is obtained, and the variation law of the surface charge potential with time is given. The results show that when the plasma is two-Maxwellian, the surface charge potential of the spacecraft is lower than the surface charge potential under the single Maxwellian plasma environment. The plasma assumption of the single Maxwellian distribution will overestimate the charge effect of the spacecraft surface. In the second distribution function of the two-Maxwell distribution, the ion composition mainly affects the final equilibrium charge potential of the surface. The higher the number density or temperature of the double-Maxwell distribution plasma, the more time it takes for the surface to reach equilibrium Long; unit capacitance only affects the surface charge potential to stabilize the time required for the final charge balance potential value has little effect.