用于太阳速度场探测的多普勒非对称空间外差关键技术研究

Doppler solar speed observation can be used to infer the inner structure of the Sun, invert the chemical compositions, the equation of state and forecast the space environment between the Sun and the Earth. It is helpful for the understanding of intense solar activity, law of development and revealing the physical nature of solar activity combined with magnetic field analysis. Limited by the difficulty of traditional observing methods, the data quantity and accuracy of solar speed detection is not enough..The project is based on the Doppler asymmetric spatial heterodyne spectroscopy. The baseline of strong background spectrum is removed in the frequency domain using the solar Fraunhofer lines, and then the target spectrum is mirrored. The phase information of sampling points of frequency domain is calculated to resolve the Doppler shift. The spectral and radiation response variation is synchronously monitored by dual reference lines. The inverted result of Doppler shift can be calibrated by calculating the phase shift of the experimental breadboard, so the detection accuracy can be improved..The aims of the project include designing and building experimental breadboard, researching phase extracting method of absorption spectra, phase synchronous tracking technique based on dual reference lines, and frequency shift simulation experiment in room. The experimental error will be used to re-guide the research of mechanization and the improvement of processing method..The project will provide a high precision detection method of solar speed. The technique has the ability to detect speed field and magnetic field synchronously, and can support the deep research of solar inner structure and evolution.

观测太阳速度场可以推测太阳内部结构，反演太阳的物态方程和预报日地空间环境等，结合磁场解析能够深入了解太阳活动的发生、发展规律，揭示太阳活动的物理本质。受限于传统观测技术工程实现难度大，观测数据数量和精度都存在不足。.本项目基于多普勒非对称空间外差光谱技术，利用太阳夫琅禾费线，通过频域强背景光谱基线去除和目标谱线镜像处理，计算干涉域采样点的相位信息从而解算多普勒频移量；利用双基准线实时跟踪系统相位漂移，同步监测试验装置光谱和辐射响应变化，从而对多普勒频移反演结果进行系统校准，提高探测精度。.搭建探测试验装置，开展吸收谱线相位提取算法、双基准线系统相位同步跟踪技术及室内频移模拟测量验证实验，通过实验误差分析重新反馈指导机理研究、处理方法的改进。.项目开展将为太阳速度场的高精度探测提供新的技术手段，该技术具备同时实现速度场和磁场探测的潜力，支持太阳内部结构和演化的深入研究。

太阳多普勒速度场探测可以推测太阳内部结构，反演太阳的化学组成、物态方程和预报日地空间环境等，有利于深入了解太阳剧烈活动的发生、发展规律。多普勒非对称空间外差光谱技术（DASH）继承传统空间外差光谱技术高光谱分辨率、波段任意选择、光通量大及集成度高等诸多优点基础上，通过增大单臂光栅偏置量实现同时探测多个谱线在大光程差处的相位变化，易于实现高精度的多普勒频移探测。.在DASH理论模型的基础上，针对太阳速度场探测需求对干涉仪关键指标进行理论分析和推导，明确系统参数设计的理论依据。开展了系统敏感因素仿真分析和参数设计，对干涉仪光学元件误差（分束器、扩视场棱镜、光栅等）、系统噪声和环境变化等因素产生的基频漂移、绝对相位误差和速度误差进行了仿真和定量分析；根据探测需求，设计系统的详细参数，并完成了干涉仪的加工，利用谱线灯对干涉仪性能进行标定，验证了理论分析正确性，定标结果表明设计值与实测值一致。.基于高速转盘方案设计、加工了频移模拟装置，并且定量分析了频移模拟器的模拟速度误差，给出总速度模拟误差约为1.3%，明确模拟误差主要因素为夹角误差和有效半径测量误差；对测试验证系统进行了集成，开展了34.19 m/s到78.63 m/s范围内多组数据测量；建立了速度反演数据处理流程，针对窗函数选择，通过分析比较确定半高宽为2的Nuttall窗函数。对测速误差因素进行了理论分析，最终实现2.92m/s的实验室速度模拟探测精度。