基于双DKDP晶体原理的太阳大气实时偏振探测技术研究  

Real Time Polarization Detection of Solar AtmosphereBased on Double DKDP Crystals Principle

作　　者：胡平 顾乃庭[1,2] 饶长辉[1,2] Hu Ping;Gu Naiting;Rao Changhui(Institute of Optics and Electronics,Chinese Academy of Sciences,Chengdu 610209,China;Key Laboratory of Adaptive Optics,Chinese Academy of Sciences,Chengdu 610209,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院光电技术研究所,四川成都610209 [2]中国科学院自适应光学重点实验室,四川成都610209 [3]中国科学院大学,北京100049

出　　处：《天文研究与技术》2021年第4期544-553,共10页Astronomical Research & Technology

基　　金：国家自然科学基金(61905252,12022308)资助.

摘　　要：磁场是太阳爆发活动的根本驱动力,高精度实时偏振测量是实现磁场测量的常用方法。常用的波片式测量方法需要进行多次测量,因存在机械旋转结构,易导致仪器抖动,降低测量精度;波片旋转或切入切出也会导致测量时间较长。目前,基于磷酸二氘钾(DKDP)晶体和波片的太阳大气偏振测量周期较长,实时性不高,无法应用于快速变化的太阳活动磁场探测。根据以上背景,提出了一种基于双DKDP晶体原理的太阳大气实时偏振探测技术,采用两片快轴方向不同的DKDP晶体,通过外加不同电压进行快速相位延迟变化,实现对入射太阳光的偏振调制,获取太阳大气偏振的斯托克斯(Stokes)矢量。相较于传统旋转波片与DKDP晶体相结合的方法,本文提出的方法可将单次偏振调制速率从数秒提高到毫秒级,极大地提高了太阳磁场测量的实时性。仿真分析结果表明,本文提出的方法测量精度达到2×10-3,单波长点测量时间分辨率提高了20倍以上,可以实现对太阳磁场偏振信息的实时精确测量。Magnetic field is the fundamental driving force of solar eruptions.High precision real-time polarization measurement is a common method to realize magnetic field measurement.However,the commonly used wave plate measurement method needs to be measured many times,and there is a mechanical rotation structure,which can easily cause instrument jitter and reduce the measurement accuracy;the rotation or switching of wave plate also leads to a longer measurement time.At present,the measurement period of solar atmospheric polarization based on DKDP crystal and wave plate is long,and the real-time performance is too low to be applied to the detection of rapidly changing solar active magnetic field.Based on the above background,this paper proposes a real-time polarization detection technology of the solar atmosphere based on the principle of double DKDP crystals.Two DKDP crystals with different fast axis directions are used to realize the polarization modulation of the incident sunlight and obtain the polarization Stokes vector of the solar atmosphere.Compared with the traditional method of combining rotating wave plate and DKDP crystal,the proposed method can increase the single polarization modulation rate from several seconds to millisecond,which greatly improves the real-time performance of solar magnetic field measurement.The simulation results show that the measurement accuracy of the proposed method is 2×10-3,and the measurement time resolution of single wavelength point is improved by more than 20 times,which can realize the real-time accurate measurement of the polarization information of solar magnetic field.

关 键 词：太阳磁场 偏振测量 DKDP 实时测量 

分 类 号：P161.3[天文地球—天文学]