利用立体观测降低太阳磁场测量误差  

Reducing the Measuring Error of Solar Magnetic Field by Stereo Observation

作　　者：曾柏予 郭洋 李川[1] 李臻 尤伟[2] 黄帆[2] 张兰强[3] 杨金生[3] ZENG Bai-yu;GUO Yang;LI Chuan;LI Zhen;YOU Wei;HUANG Fan;ZHANG Lan-qiang;YANG Jin-sheng(School of Astronomy and Space Science,Nanjing University,Nanjing 210023;Shanghai Institute of Satellite Engineering,Shanghai 200240;Institute of Optics and Electronics,Chinese Academy of Sciences,Chengdu 610209)

机构地区：[1]南京大学天文与空间科学学院,南京210023 [2]上海卫星工程研究所,上海200240 [3]中国科学院光电技术研究所,成都610209

出　　处：《天文学报》2024年第5期121-130,共10页Acta Astronomica Sinica

基　　金：国家自然科学基金项目(12333009);国家重点研发计划(2022YFF0503004);国家航天局民用航天技术预先研究项目“太阳全方位立体探测系统设计与关键技术”资助。

摘　　要：塞曼效应是目前测量太阳磁场最主要的方法,但使用塞曼效应观测存在两个问题:测量到的矢量磁场中,垂直于视线方向的磁场(横场)方向存在180°不确定性;同时,横场的测量精度也要比沿视线方向的磁场(纵场)低一个量级.可以通过在不同的视线方向立体观测磁场去除180°不确定性并且提高太阳磁场横场的测量精度.重点讨论联合日地L5点和日地连线方向的观测提高横场测量精度的问题,同时通过模型建构与数据定量分析,得出横场误差的减小量.通过球面三角公式,求得地球和L5点磁场的坐标关系,由标准偏差传递公式得到修正后的地球处的测量误差;统计日震和磁场成像仪(Helioseismic and Magnetic Imager,HMI)观测到的太阳磁场误差的数据分布,模拟出两幅符合太阳磁场分布的数据,分别作为地球和L5点的误差图;结合地球和L5点数据,得出地球横场误差的修正数据并与原始横场数据进行对比,发现可以使地球处观测的黄道面上的横场误差降低为原来的17%左右.Observing the solar magnetic field from a single point,we can measure the magnetic field along the line of sight and the magnetic field perpendicular to the line of sight(transverse field).However,the accuracy of transverse field is one order of magnitude lower than that of the radial field,and there is a 180°uncertainty in the direction of the transverse magnetic field.The goal of this paper is to improve the accuracy of the transverse field of the solar magnetic field.It is considered to observe the magnetic field at L5 point and Earth simultaneously,and the error reduction can be obtained through model construction and data analysis.The specific methods are as follows:Coordinate relations of magnetic fields at Earth and L5 point are obtained by spherical trigonometry formula,and the corrected errors of the transverse magnetic field at L1 points are obtained by error transfer formulae;Calculate the error distribution of the solar magnetic field data,and simulate two data conforming to the solar magnetic field distribution,which are respectively used as the error diagram of Earth and L5 point;By combining the data of Earth and L5 point,the corrected data of the transverse field error at Earth are obtained and compared with the original transverse field data.It is found that the transverse field error of Earth can be reduced to about 17%of the original.

关 键 词：航天器:仪器 方法:统计 太阳:磁场 

分 类 号：P171[天文地球—天文学]