嫦娥一号卫星太阳风离子探测器离子流量反演太阳风参数与初步结果分析

In-flight Experiment of Solar Wind Ion Detectors on Chang'E-1 and the Solar Wind Near the Moon

嫦娥一号卫星（Chang’E．1）上搭载的两台太阳风离子探测器（SWID—A／B）是国际上首次在200km极月轨道观测等离子体环境的探测仪器．SWID—A／B的科学目标是探测月球附近等离子体与月球的相互作用，获得月球附近的太阳风速度、密度和温度．太阳风离子探测器的观测数据是各能量成分离子流量的直接反映，包含了太阳风离子的速度、密度和温度信息．本文设计了一种利用离子流量数据反演太阳风速度、密度和温度的算法，并通过模拟太阳风离子注入探测器的过程，验证了算法的可行性．对月球附近太阳风离子基本特征的分析研究表明，在太阳活动低年，空间环境扰动水平相对较低时，行星际太阳风运动到月球附近后依然保持着相同的变化趋势；太阳风离子的速度和密度与在上游行星际空间时相近；太阳风离子的温度则比在上游行星际空间时高103K．

It＇s the first time for the two scientific instruments of Solar Wind Ion Detectors （SWID- A/B） on Chang＇E-1 to explore the plasma environment in the 200kin lunar polar orbit. SWIDs are primarily developed for the scientific objectives of measuring the Moon-plasma interactions, and deducing the solar wind bulk speed, density and temperature. SWIDs observe the ions fluxes which include the information of solar wind speed, density and temperature. In this paper, the algorithm of deducing the solar wind bulk speed, density and temperature by the observation results of SWID- A/B is shown. By simulating the solar wind ions injecting to the SWIDs, the algorithm is validated. The characteristics of solar wind near the Moon are studied. During the period of the Sun disturbing comparatively quiet in solar minimum, it is found that the similar trend of variation is maintained when the solar wind go through the interplanetary to the Moon. Whereas the solar wind ions speed and density are the same to those of the upstream interplanetary solar wind, the solar wind temperature near the Moon is 103K higher than that of the upstream interplanetary solar wind.