YNAO OpenIR研究单元&专题: 光纤阵列太阳光学望远镜研究组
http://ir.ynao.ac.cn:80/handle/114a53/55
2024-03-28T13:20:38Z
2024-03-28T13:20:38Z
基于连续式旋转波片调制的傅里叶解调方法研究
林哲宇
http://ir.ynao.ac.cn:80/handle/114a53/26418
2024-03-26T06:35:11Z
2024-03-26T06:35:11Z
题名: 基于连续式旋转波片调制的傅里叶解调方法研究
作者: 林哲宇
摘要: Polarized radiometry is an important means to obtain the physical state of astrophysical objects. The anisotropy of the light source or propagation path is the main mechanism leading to the generation of polarization. Therefore, polarized radiation can provide important information about vector fields such as the magnetic field or radiation field of astronomical objects. In the physics of solar measurement, using certain atomic spectral lines to measure high-precision polarized radiation is the main means to detect the solar vector magnetic field at present. When we measure the polarization of the solar magnetic field, two processes of polarization modulation and polarization demodulation are involved. The purpose of polarization modulation is to modulate the polarization signal into an observable intensity signal, which is mainly realized by the polarization analyzer. For different scientific objectives, the types of polarization analyzers are also different, and the polarization modulator either uses a rotating wave plate or controls a variable liquid crystal wave plate to realize polarization signal modulation. Polarization demodulation is the process of recovering the polarization signal from the observed intensity signal.When a rotating wave plate is used as a polarization modulator, it can be divided into a step modulation mode and a continuous modulation mode according to different rotation modes. The continuous modulation mode is widely used due to its high time resolution. At present, the "dual beam + continuous" modulation scheme is the mainstream polarization measurement scheme in the world. Therefore, this paper mainly studies the demodulation method in the continuous rotating wave plate modulation mode in polarization measurement. The main results and conclusions of the research are as follows:(1) Deduce the Fourier demodulation formula under the continuous modulation mode, use numerical simulation to simulate the demodulation process, compare the residual error between the demodulated signal and the input signal, and verify the correctness of the Fourier demodulation formula .(2) Use simulation to quantitatively analyze the demodulation performance of Fourier demodulation and matrix demodulation under the action of common errors in continuous modulation. The errors analyzed in this work include the initial azimuth error of the wave plate and the positioning accuracy error of the wave plate It is found that the demodulation performance of the two is basically the same, and the error range under the requirement of high-precision continuous modulation is given in the paper. In the process of demodulation performance analysis, the effects of wave plate retardance and modulation times on polarization efficiency are considered at the same time, and the optimized wave plate retardance and appropriate modulation times of continuous modulation are adopted.(3) A series of related actual measurements were carried out in combination with the laboratory adjustment of the FASOT polarization analyzer. The actual included angle between the transmission axes of the four polarizers in the calibration unit and the measured retardation of the purchased commercial wave plate are calculated by using the light intensity method.
摘要: 偏振辐射测量是获得天体物理状态的一种重要手段,光源或传播路径的各向异性是导致偏振产生的主要机制,因此偏振辐射可以提供有关天体磁场或辐射场等矢量场的重要信息。在太阳实测物理中,利用某些原子谱线进行高精度偏振辐射测量是目前探测太阳矢量磁场的主要手段。当我们对太阳磁场进行偏振测量时,涉及到偏振调制和偏振解调两个过程。偏振调制目的是将偏振信号调制进入可观测的强度信号,主要由偏振分析器实现。而针对不同科学目标,偏振分析器的类型也不尽相同,其中的偏振调制器或采用旋转波片或控制可变液晶波片来实现偏振信号调制。偏振解调则是从观测到的强度信号中还原出偏振信号的过程。 当采用旋转波片作为偏振调制器的时候,根据旋转方式不同分为步进式调制模式和连续式调制模式,连续式调制模式由于时间分辨率较高而被广泛采用。目前“双光束+连续式”的调制方案是国际上比较主流的偏振测量方案。故而本文主要对偏振测量中连续式旋转波片调制模式下的解调方式进行研究,研究的主要成果和结论为:(1)推导连续式调制模式下的傅里叶解调公式,利用数值仿真模拟该解调过程,对比解调信号与输入信号之间的残差,验证了傅里叶解调公式的正确性。(2)利用模拟仿真,定量分析傅里叶解调和矩阵解调在连续式调制常见误差作用下的解调性能,本工作分析的误差包括了波片初始方位角误差、波片定位精度误差和波片旋转与相机不匹配误差,分析发现两者的解调性能基本一致,并在文中给出了高精度连续式调制要求下的误差范围。在解调性能分析过程中,同时考虑了波片延迟量和调制次数对偏振效率的影响,采用了连续式调制的优化波片延迟量和适当调制次数。(3)结合FASOT偏振分析器的实验室装调开展了系列相关的实测。利用光强法计算出了其定标单元中4个偏振片透过轴之间的实际夹角及其所购置的商业波片的实测延迟量。
2024-03-26T06:35:11Z
太阳多尺度磁活动的空间分布特征研究
张小娟
http://ir.ynao.ac.cn:80/handle/114a53/26401
2024-03-26T06:35:05Z
2024-03-26T06:24:27Z
题名: 太阳多尺度磁活动的空间分布特征研究
作者: 张小娟
摘要: Solar activities are the significant factors affecting space weather. Solar activity has a clear eleven-year periodic behaviour. Solar activity was determined by the solar magnetic field, studying the spatio-temporal variation characteristics of solar multi-scale activities is significant meaning for understanding the dynamic evolution process of the solar magnetic field. We have more opportunities to learn more about the spatial distribution of solar multi-scale activity with the advancement of astronomical observation techniques. The overall level of the sunspot in solar cycle 24 decreased much compared to cycle 23, while the number of coronal ejections increased much compared to solar cycle 23. The evolution of the magnetic field is derived from solar rotation. This paper focuses on the spatial distribution of solar multi-scale magnetic activities by studying the sunspot relative numbers, coronal mass ejection database, and Lyman-𝛼 irradiance. Here, we clear that the normalization factor of the normalized asymmetry index has an unusually large influence on the results of the asymmetry index at very low levels of sunspot activity by studying the relative sunspot numbers over the last hundred years, and we determined that the absolute asymmetry index is the most appropriate index for the research of hemispheric asymmetry. Our results provide a stage of progress in the study of hemispheric asymmetry of solar activity indices over the last 50 years. In addition, quasi-biennial oscillations, around 8.5 years and 30-50 years were found in the hemispheric distribution, this result corroborates the numerical simulations of the dynamo theory. Based on high-quality observations from the Large Angle Spectroscopic Coronagraph at the Solar Heliospheric Observatory from 1996 to 2020, this paper divides coronal mass ejections into regular and specific coronal mass ejections. And find that the hemispheric distribution of regular coronal mass ejections is closely related to the hemispheric distribution of sunspot activity, while the hemispheric distribution of specific coronal mass ejections is not related to the hemispheric distribution of sunspot activity, but is closely related to the coronal and heliospheric environment. The hemispheric asymmetry of coronal mass ejections is mainly caused by special coronal mass ejections, not the regular coronal mass ejections. Besides, high-latitude (associated with polar filament and jets) and low-latitude (associated with sunspot activity) events produce in different source regions, so their hemispheric distributions do have different features implying that the hemispheric distribution of coronal mass ejections is a function of the latitude. The dominant hemisphere, cumulative trend, and amplitude distribution of coronal mass ejections differ significantly during different solar cycles, indicating that the heliospheric environment, photospheric magnetic field, and meridional circulation play an important role in the evolution of coronal mass ejections. The investigation of the source locations of halo coronal mass ejections shows that the hemispheric distribution of source locations of the halo coronal mass ejections is also asymmetrical, and the source locations of the halo coronal mass ejections are mainly concentrated in the latitudes of the solar activity region, which is closely related to the sunspot activity, and there is no ”rush to the polar region” phenomenon exists in the distribution of the source locations of halo coronal mass ejections. The investigation of the Lyman-𝛼 irradiance from 1947 to 2023 shows that there are two rotation signals of 27.8 and 13.9 days for the solar transition region. The periodic signal of 13 days was obvious in the works of the periodicity behavior of the solar wind velocities and interplanetary magnetic field. This result suggests that solar rotation of the transition region plays an important role in the solar wind, and provides some guidance for the adjustment of solar wind model parameters. It is also found that the solar rotation of the transition region ranges from 19.25 to 31.25 days (mean value is 25.45 days ), with a decreasing trend. The rotation of the solar transition region is closely related to the 11-year cycle of sunspot activity. Coronal mass ejections and solar wind are significant astronomical factors affecting the solar-terrestrial space environment, this paper focuses on the study of the variation of multi-scale solar magnetic activities with solar cycles, especially for the evolution characteristics of the hemispheric distribution of the coronal mass ejections and the rotation of the solar transition region. The results provide new observational results for further understanding the variation of the solar-terrestrial space environment.
摘要: 太阳的剧烈爆发活动是影响空间环境的重要因素。太阳活动存在明显的11年周期,研究不同尺度太阳活动的时空分布特征对了解太阳磁场的动力学演化过程有重要的意义。 天文观测技术的进步创造更多的机会了解不同尺度太阳活动的时空分布特征。黑子在第 24 太阳活动周的整体活动水平相比第23活动周是降低的;日冕物质抛射在第 24 活动周的发生数相较于第 23 活动周却是增加的。同为太阳磁活动指数代表的黑子和日冕物质抛射,其整体活动水平是不同的。太阳磁场的动力学演化离不开太阳自转,本文基于太阳黑子相对数,日冕物质抛射数据库和 Lyman-𝛼 辐照度来展开对太阳多尺度磁活动的空间分布特征研究。 本文通过研究近百年的太阳黑子相对数,明确了在太阳黑子活动水平极小的情况下,归一化不对称指数的归一化因子会对不对称指数结果造成异常大的 影响,并因此确定绝对不对称指数是最合适的半球不对称特征的表征指数。这为近 50 年来太阳活动半球不对称指数的表征问题提供了阶段性的研究进展。同 时,发现黑子活动的半球不对称特征存在准双年振荡、8.5 年左右和 30-50 年这 三个特征周期,这些准周期丰富了太阳磁结构空间分布的观测特征,为通量传输发电机理论中磁场的演化与转化过程提供了观测和统计上新的约束。 基于太阳日球天文台(SOHO)上的大视角分光日冕仪(LASCO)从1996年到2020年的高质量观测数据,本文将日冕物质抛射分为常规日冕物质抛射和 特殊日冕物质抛射,常规日冕物质抛射的半球分布和太阳黑子活动的半球分布 密切相关,而特殊日冕物质抛射的半球分布和黑子活动的半球分布不相关,和日冕以及日球环境密切相关。日冕物质抛射随活动周的分布存在半球不对称特征,这种半球不对称特征主要是由特殊日冕物质抛射引起的,常规日冕物质抛射的贡献为次要因素;高纬度(与极冠暗条和喷流等相关)和低纬度(与活动周或黑 子相关)事件产生的源区不同,它们的南北半球分布不一致,这意味着日冕物质抛射的半球分布是纬度的函数。另外,在不同的太阳活动周,日冕物质抛射的优势半球、累加趋势和幅度分布存在显著的差异,这种差异可能是由于不同活动周的日球环境、光球磁场和子午环流的变化。进一步研究晕状日冕物质抛射的源区位置发现,晕状日冕物质抛射的源区同样存在半球不对称特征,这种半球不对称特征在不同活动周的演化规律是不同的;且还发现晕状日冕物质抛射的源区主要集中于太阳活动区纬度,和黑子活动密切相关,不存在“冲向极区”现象。 研究 Lyman-𝛼 辐照度从1947年至2023年的变化,发现太阳过渡区自转存在27.8天和13.9天两个特征周期,其中13天的周期行为同样存在于太阳风速 度和行星际磁场的周期研究中,这一结果表明太阳过渡区自转在太阳风中有着重要作用,为太阳风模型参数的调整提供一定的参考价值。另外还发现,太阳过渡区自转周期范围是19.25至31.25天,且长期来看呈现下降趋势。太阳过渡区自转和黑子交叉相关分析结果显示,太阳过渡区自转和黑子活动的11年周期特征联系密切。 日冕物质抛射和太阳风均是直接影响日地空间环境的重要天文学因素,本文主要聚焦于对不同尺度太阳活动随活动周变化的研究,特别是日冕物质抛射随活动周的演化特征研究,以及太阳过渡区自转特征的研究,为进一步了解日地空间环境提供了新的观测依据。
2024-03-26T06:24:27Z
FASOT-2望远镜的宽波段偏振分析器的设计与实测
万凡
http://ir.ynao.ac.cn:80/handle/114a53/26399
2024-03-26T06:35:05Z
2024-03-26T06:24:26Z
题名: FASOT-2望远镜的宽波段偏振分析器的设计与实测
作者: 万凡
摘要: The accurate measurement of the solar atmospheric vector magnetic field is important for the analysis of the generation and connection of various violent activities in the solar atmosphere. At present, the precise measurement of the magnetic field is mainly based on the high-precision polarimetry of magneto-sensitive lines caused by Zeeman effect and magneto-optical effect. In order to obtain high-precision magnetic field information, solar physicists demand high precision in the polarimetry of the telescope. Nowadays, the polarimeric accuracy of the current mainstream solar optical telescopes is 10−3Ic ~ 10−4Ic . If the polarimetric accuracy wants to be improved further, the polarimetric errors that may be introduced by each subsystem of the telescope need to be analyzed and suppressed more finely.Fiber Array Solar Optical Telescope of the second generation (FASOT-2), which is being developed by Yunnan Observatories, Chinese Academy of Sciences, aims to simultaneously measure polarization signals of two-dimensional of the target source and that of spectral lines at different atmospheric depths. The polarimetric accuracy of FASOT-2 is required to reach 8 × 10−4𝐼𝑐 . In order to achieve the scientific observation target of FASOT-2 telescope with high polarimetric accuracy over broad band, the polarimetric errors that may be introduced by each subsystem of FASOT-2 telescope need to be carefully calculated and suppressed. As one of the core terminal devices of the solar optical telescope to measure the magnetic field, it is necessary to analyze the polarimetric performance of the polarimeter in detail. in this paper, the three studies have been carried out on the polarimetric system of FASOT-2 telescope.1. A dual-beam polarimeter with high polarimetric efficiency over the wide band has been designed, which can meet the scientific goal of the FASOT-2 telescope for high-precision measurements of target magneto-sensitive lines over 500nm∼900nm. The polarimetric efficiency satisfies 𝜖𝑄𝑖𝑛/𝐼𝑖𝑛 ≥ 0.5, 𝜖𝑈𝑖𝑛/𝐼𝑖𝑛 ≥ 0.51, 𝜖𝑉𝑖𝑛/𝐼𝑖𝑛 ≥ 0.52, 𝜖𝑡𝑜𝑙 ≥ 0.98, and the efficiency balance among them is also well guaranteed. In addition, the polychromatic characteristic of the polarimeier is achieved by using non-achromatic waveplates as the modulator, which avoids the defect, sensitive to ambient temperature or applied voltage, of liquid crystal materials (FLC, LCVR). And the stability of waveplates is higher, but the time resolution is lower than that of liquid crystal materials. The non-achromatic waveplates also avoids the defect that the retardance of the super-achromatic waveplates over the wide band is not accurate. Furthmore, the non-achromatic waveplates can be more available in the market. The polarimeter designed in this paper has the features of simple structure, high stability, strong anti-interference and simple maintenance. Moreover, it adopts the modulation method of Reduced Polarimetric Optics Switching(RPOS), which can minimize the polarimetric errors introduced by the telluric Seeing and different gain factors along different beam paths at the same time. In addition, the polarimeter is combined with the calibration unit to minimize the additional polarimetric errors introduced by the telescope itself. Thus the polarimetric accuracy of the telescope can be improved further.2. The parameters such as the retardance 𝛿 and fast-axis azimuth 𝜃 of the non-achromatic waveplates that constitute the wide-band polarimeter and the polarization calibration unit are accurately measured and corrected, which can further minimize the polarimetric errors introduced by the manufacturing defects of optical components. In this paper, a measurement system based on the fitted intensity method and the spectral analysis method is established, which can achieve high accuracy measurement for non-achromatic waveplates with the retardance over 0 ∼ 2𝜋. The measurement accuracy of the waveplate with retardance ≠ 𝜋 is higher than that of the conventional optical intensity method more than one order of magnitude, and the spectral analysis method based on this measurement system can overcome the defect that the optical intensity method cannot measure the waveplate with the retardance of 𝜋. And the measurement accuracy of the waveplates with the retardance near 𝜋 is higher by using the spectral analysis method. The measurement system can be used to accurately measure and calibrate the the retardances of the non-achromatic half waveplates and quarter waveplates, a part of polychromatic polarimeter.3. The polarimetric efficiency of the assembled polychromatic polarimeter should be actually measured in the laboratory and compared with the theoretical values before it is installed on the telescope. In order to quantitatively measure the polarimetric errors that may be introduced by mounting errors and further analyze the effect of this bias on the performance of the FASOT-2 telescope. The research of the polarimetric efficiency of the polychromatic polarimeter is based on the measurement of the Mueller matrix at a certain wavelength point and a certain modulation state. By repeatedly measuring the Mueller matrix of the polarimeter at different modulation states, the modulation matrix O can be obtained, and then the demodulation matrix D is obtained by calculating the generalized inverse matrix of the O. Finally, according to the definition of the polarimetric efficiency, thus the polarimetric efficiency(𝜖𝑄𝑖𝑛/𝐼𝑖𝑛,𝜖𝑈𝑖𝑛/𝐼𝑖𝑛,𝜖𝑉𝑖𝑛/𝐼𝑖𝑛,𝜖𝑡𝑜𝑙) of polychromatic polarimeter at a particular wavelength point can be obtained. By changing the dispersion center wavelength of the spectrometer, the polarimetric efficiency of the polarimeter at 500nm∼900nm can be measured. The measured results show that the polarimetric efficiency has little deviation from the theoretical value after excluding the errors introduced by other subsystems of the telescope. And the polychromatic polarimeter is not sensitive to the installation errors of optical components. So the polarimetric errors of the telescope are not be introduced by the polarimetric sys tem. Therefore, the source analysis and suppression of polarimetric errors of FASOT-2 telescope may be more focused on other subsystems.In this paper, a dual-beam polychromatic polarimeter of the FASOT-2 telescope with high polarimetric efficiency over the wide band has been designed, and the accurate measurement of the retardance of the waveplates, the optical components used in the polarimetric system, have been completed. In addition, the actual measurement of the polarimetric efficiencies of the polychromatic polarimeter over the broad band have also been completed. The measured results confirm the superior performance of the designed polychromatic polarimeter. This is an important step for the FASOT-2 telescope to achieve high precision polarization measurement over the wide band.Key Words: FASOT-2 telescope, Polychromatic polarimeter, High polarimetric efficiency, Accurate measurement of the retardance, Accurate measurement of Mueller matrix
摘要: 太阳大气矢量磁场的精细研究对分析太阳大气各种剧烈活动的产生与联系具有重要意义。目前对于磁场的精确测量主要是基于塞曼效应与各种磁光效应对目标源的磁敏线进行高精度的偏振测量。为了获得高精度的磁场信息,太阳物理学家们对望远镜的偏振测量精度提出了较高的要求。目前国内外主流的太阳光学望远镜的偏振测量精度普遍都在 10−3𝐼𝑐 ∼ 10−4𝐼𝑐 量级,若想在此基础上进一步提高望远镜的偏振测量精度,则需要对望远镜的各子系统可能引入的偏振 测量误差进行更精细的分析并加以抑制。 中国科学院云南天文台正在研制的第二代光纤阵列太阳光学望远镜 (Fiber Array Solar Optical Telescope of the second generation,FASOT-2) 致力于同时测量待测目标源的二维平面偏振信号与不同大气深度的磁敏线偏振信号,且偏振测量精度要求达到 8 × 10−4𝐼𝑐 量级。为了达到如此高的偏振测量精度,对 FASOT-2 望远镜的各子系统可能引入的偏振测量误差均需要精细的计算并加以抑制。而偏振测量系统作为望远镜的核心系终端设备之一,对偏振分析器的偏振性能进行详细的分析是十分有必要的。本文立足于 FASOT-2 望远镜的偏振测量系统主要进行了以下三个研究工作。 1.设计了一款宽波段的高偏振测量效率的双光束偏振分析器,满足了FASOT- 2 望远镜对分布在500nm∼900nm 的目标磁敏线同时进行高精度测量的科学目的。在整个波段内各磁敏线的偏振测量效率满足 𝜖𝑄𝑖𝑛/𝐼𝑖𝑛 ≥ 0.5,𝜖𝑈𝑖𝑛/𝐼𝑖𝑛 ≥ 0.51, 𝜖𝑉𝑖𝑛/𝐼𝑖𝑛 ≥ 0.52,𝜖𝑡𝑜𝑙 ≥ 0.98,且各偏振分量的效率平衡也得到了保证,有效的抑制了接收光强误差引入的偏振测量误差。并且设计的偏振分析器采用非消色差波片作为偏振调制器实现消色差特性,避免了使用液晶材料 (FLC、LCVR) 作为调制器对环境温度或外加电压敏感的缺陷,其稳定性更高,但不可避免的会牺牲一 定的时间分辨率。也避免了采用超消色差波片作为偏振调制器其延迟量在宽波 段范围内不准确引入的偏振测量误差。设计的双光束偏振分析器整体结构简单、 稳定性高、抗干扰性强、维护简单。且该偏振分析器还采用约化偏振光学开关进 行偏振调制,可同时极小化大气视宁度 Seeing 与双光束路径增益因子不同引入 的偏振测量误差。此外,采用偏振分析器与定标单元相结合的定标方式,极小化望远镜引入的附加偏振,进一步提高望远镜的偏振测量精度。2. 对构成宽波段偏振分析器与偏振定标单元的非消色差波片的性能参数如 延迟量 𝛿 与快轴方位角 𝜃 进行精确的测量并加以校正,消除由于光学元器件制 造缺陷引入的偏振测量误差。本文在拟合光强法的基础上结合光谱分析法设计了一套测量系统,对延迟量分布在 0 ∼ 2𝜋 范围内的非消色差波片均能实现高精度的测量。 利用拟合光强法测量延迟量 ≠ 𝜋 的波片其测量精度比传统的光强法高一个数量级以上。并在此测量系统上结合光谱分析法可克服光强法不能测量波片延迟量在 𝜋 附近的缺陷,对于延迟量在 𝜋 附近的波片,光谱分析法的测量精度很高。利用该测量系统对组成宽波段偏振分析器与偏振定标单元的非消色 差波片进行精确的测量定标。3. 将组装成功的偏振分析器安装到望远镜的后端之前,在实验室对其偏振 测量效率进行实际测量。在排除了 FASOT-2 望远镜其它子系统可能耦合进的偏振测量误差,单独对偏振分析器自身的性能进行定标,测量其实际测量效率并与理论值进行对比,定量的分析可能由于安装误差引入的测量误差并加以校正。对宽波段偏振分析器的偏振测量效率的实测方法研究是基于对偏振分析器处于某 一波长点某一调制态下 Mueller 矩阵的测量。通过测量偏振分析器处于不同调制 态的 Mueller 矩阵,得到调制矩阵 𝐎,再通过对调制矩阵求广义逆矩阵得到解调矩阵 𝐃,最终得到偏振分析器处于某一 波长点的实测偏振测量效率 (𝜖𝑄𝑖𝑛/𝐼𝑖𝑛,𝜖𝑈𝑖𝑛/𝐼𝑖𝑛,𝜖𝑉𝑖𝑛/𝐼𝑖𝑛,𝜖𝑡𝑜𝑙)。即可测量出偏振分析器在各波长采样点的偏振测量效率。由实测结果可知,在排除望远镜其它子系统的误差干扰后,偏振分析器自身的偏振测量效率与 理论设计值偏差很小,且偏振分析器自身对于元器件的安装误差不敏感,整个偏 振测量系统引入的偏振测量误差较小。因此偏振测量误差来源分析及抑制可能 更着重于 FASOT-2 望远镜其它子系统。本文的研究工作完成了 FASOT-2 望远镜宽波段高偏振测量效率的双光束偏 振分析器的设计,偏振测量系统所使用波片的延迟量的精确测量与偏振分析器 的偏振测量效率的实测定标。为 FASOT-2 望远镜实现宽波段高精度偏振测量的 科学目的踏出了重要的一步。关键词: FASOT-2 望远镜,宽波段偏振分析器,高偏振测量效率,波片延迟量 测量,Mueller 矩阵测量
2024-03-26T06:24:26Z
波片延迟量在0°~360°的高精度测量方法研究
万凡
钟悦
屈中权
徐稚
张辉
彭洋
http://ir.ynao.ac.cn:80/handle/114a53/26068
2023-08-30T18:00:13Z
2023-06-19T09:10:48Z
题名: 波片延迟量在0°~360°的高精度测量方法研究
作者: 万凡; 钟悦; 屈中权; 徐稚; 张辉; 彭洋
摘要: <p>and spectral analysis method, which can realize the high-precision measurement of the retardance of nonachromatic waveplates at 0°~360°. The measuring system is composed of a white light source, an aperture diaphragm, a narrow band filter, a Glan Taylor prism as polarization generator, a non-achromatic waveplate to be measured, a Glan Taylor prism as polarization analyzer, an optical power meter or spectrometer. When the phase retardance and the fast-axis position angel of non-achromatic waveplates are measured by the fitting light intensity method, the white light emitted by the white light source is collimated parallel by the collimating system, then it passes through an aperture diaphragm, a narrow filter and a polarization generator, which is modulated into monochromatic linearly polarized light. Next the linearly polarized light goes through the waveplates and the polarization analyzer, is finally received by the optical power meter. During the whole measuring process, the high precision motor drives non-achromatic waveplates that are to be measured to rotate uniformly. However, in the measurement process of spectral analysis measuring method, it is necessary to move the narrow filter out of the optical measurement path, and replace the power meter with the spectrometer as the terminal detection device, in this case, nonachromatic waveplates are not needed to rotate by the motor. Before the formal measurement of the retardance and the initial fast-axis position angle of waveplates, the stability of the measurement system and the sources of measurement errors are analyzed in detail in this paper. Under the light intensity measurement method, the influence of random errors such as light source intensity jetter, the initial fastaxis position angle and the rotating position angle of the rotating waveplate and some system errors like nonlinear effects of photoelectric response of the powermeter and deviation of collimated beam is simulated. And the reason why the fitting light intensity method can not measure the retardance at 180° of nonachromatic waveplates accurately is also analyzed detailly. Under the simulation of the spectral analysis method measuring the retardance of waveplates, we also simulate the influence caused by some random errors such as light source intensity jetter, wavelength monochromaticity and motor positioning errors. Then we suppressed the random errors mentioned above in the two measurement methods in the laboratory. And the nonlinear effect of the photoelectric response of the detector is also corrected. Finally, we measured the non-achromatic λ 4waveplate, 0. 356λ non-achromatic waveplate and λ 2 non-achromatic waveplate at 632. 8 nm by using this measurement system, and the measuring data were fitted by the nonlinear least squares method. The results of the phase retardance and fast-axis position angle of the nonachromatic waveplates were obtained. It can be seen from the actual measurement that the measurement accuracy of the retardance of the λ 4 waveplate and 0. 356λ waveplate by the fitting light intensity method is relatively high, and the measurement error is less than 0. 05°. The measurement accuracy is more than one order of magnitude higher than the traditional light intensity measuring method. Moreover, the measuring device of the fitting light intensity method is simple, fast and easy to operate. For the non-achromatic λ 2 waveplate, the spectral analysis method is adopted to measure the retardance under this system. in this case, the terminal device performed by the powermeter in the fitting light intensity method is switched by the spectrometer and Charge Coupled Device camera. And the narrow band filter is also removed in the light path. From the measurement results, we can know that the measuring error of the retardance is less than 0. 02° by this measuring method, which is much smaller than the 0. 70° of measuring error caused by the fitting light intensity method. So the spectral analysis method overcomes the defect that the retardance at 180° of the non-achromatic λ 2 waveplate can not be accurately measured by the light intensity method. Therefore, the phase retardance of non-achromatic waveplates from 0° to 360° and the fast-axis position angel can be measured accurately by the measurement system designed in this paper, which provides the basis for the accurate measurement of the polarimeter.</p>
摘要: <p>为了精确测量非消色差波片的延迟量与快轴方位角,基于拟合光强法与光谱分析法建立了一套高精度测量系统,实现了特定波长下非消色差波片延迟量在0°~360°的高精度测量。对波片延迟量的测量方法及误差来源进行了详细的模拟分析。在拟合光强法下,重点仿真了光源光强抖动变化、检偏器初始安装精度、旋转波片定位精度等随机误差与各项系统误差对测量精度的影响,详细分析了拟合光强法不能精确测量波片延迟量为180°的原因。在光谱分析法下模拟了光源光强抖动变化、光谱的单色精度、检偏器定位精度引入的测量误差。在测量系统的建立中对上述两种测量方法影响较大的误差均进行了抑制,并对探测器的光电响应非线性效应进行了矫正。最后利用该测量系统对标称的λ/4波片、0.356λ波片、λ/2波片进行了相关实测并利用非线性最小二乘法对测量数据进行处理,获得了参考波长在632.8 nm的各波片的相位延迟量与快轴方位角。由该测量系统的实测结果可知:本文采用的拟合光强法测量λ/4波片、0.356λ波片延迟量的测量误差小于0.05°,测量精度比传统光强测量法高一个数量级以上。对于λ/2非消色差波片,在该测量系统下切换终端光强接受设备并采用光谱分析法对其进行测量,测得其延迟量误差小于0.02°,远小于拟合光强法的测量误差0.70°,克服了光强法无法精确测量波片延迟量为180°的缺陷。实测结果与模拟仿真相符。 </p>
2023-06-19T09:10:48Z
Complexity of the Upper Solar Atmosphere Revealed from Spectropolarimetry during a Solar Eclipse
Qu ZQ(屈中权)
Chang L(常亮)
Dun GT(敦广涛)
Xu Z(徐稚)
Cheng XM(程向明)
Deng LH(邓林华)
Zhang XY(张霄宇)
Jin YH(金宇航)
http://ir.ynao.ac.cn:80/handle/114a53/25993
2023-06-05T05:09:04Z
2023-05-22T03:50:13Z
题名: Complexity of the Upper Solar Atmosphere Revealed from Spectropolarimetry during a Solar Eclipse
作者: Qu ZQ(屈中权); Chang L(常亮); Dun GT(敦广涛); Xu Z(徐稚); Cheng XM(程向明); Deng LH(邓林华); Zhang XY(张霄宇); Jin YH(金宇航)
摘要: <p>We analyze linear polarimetric spectrum data of solar emission lines with different formation temperatures in a visible light band from 516.3–532.6 nm, obtained during the 2013 Gabon solar eclipse using the prototype Fiber Arrayed Solar Optical Telescope. Complexities are found from the chromosphere through the transition zone to the corona at the spatial resolution limit of 2″ and temporal resolution of seconds. The observations show irregular spatial and spectral variations in linear polarization amplitudes, directions, and profile shapes. Within the observational band, spectral lines with different formation temperatures can have comparable polarization amplitudes in one spatial volume but one order difference in another, and at the same spatial volume, the amplitudes can differ by one order at different lines. The polarization amplitudes do not consistently increase with elongation in local regions. The variation in the direction of the polarization along the elongation is found from the green coronal line and the transition zone line more frequently than from the chromospheric lines. Such a variation in orientation is not synchronous for the different lines. Finally, Stokes Q/I profiles of the broad lines, such as the magnesium triplet and the green coronal line, show very diverse and complicated patterns. After pixel binning, we show that some of the complexity may be caused by the integration over different polarization sources at subresolution scales and/or along the line of sight in the optically thin layers with complex geometric corrugations.</p>
2023-05-22T03:50:13Z
用于太阳光谱测量的光纤积分视场单元系统
孙伟民
陈旭东
闫奇
耿涛
严云翔
汪盛佳
王安之
王佳斌
金夕人
蒋航
王秀
赵闯
钟悦
梁昱
宋智明
王鹏飞
http://ir.ynao.ac.cn:80/handle/114a53/25894
2023-07-17T02:48:17Z
2023-04-24T03:02:51Z
题名: 用于太阳光谱测量的光纤积分视场单元系统
作者: 孙伟民; 陈旭东; 闫奇; 耿涛; 严云翔; 汪盛佳; 王安之; 王佳斌; 金夕人; 蒋航; 王秀; 赵闯; 钟悦; 梁昱; 宋智明; 王鹏飞
摘要: <p>Astronomical three-dimensional spectral imaging technology is a real-time spectral acquisition technology for all source targets in the observation field of view. It can simultaneously obtain the spectral domain and two-dimensional spatial domain information of the target by single sampling. Optical fiber integral field unit(IFU)is the key component of astronomical threedimensional spectral imaging technology. The image plane information is subdivided into several units and transmitted to the spectrometer through the segmentation of the received image plane. In this process, the two-dimensional spread source target is reorganized into a non-interference linear array for sampling and extraction by the spectrometer, which can effectively improve the temporal resolution of astronomical observation. This paper introduces an IFU with 242fiber units, currently applied to the fiber array solar optical telescope(FASOT-1B)system of Yunnan Observatory of the Chinese Academy of Sciences. In order to meet the index requirements of FASOT-1Band obtain the observation effect of high transmission efficiency, high spectral resolution and high time resolution, the IFU adopts the structure of a microlens array and fiber array. The microlens is a regular hexagon spherical mirror, and the spatial filling rate is nearly 100%. Considering the design parameters of the front telescope system and the back-end spectrometer system of the fiber integral field-of-view unit, apair of 11×11microlens arrays is an optimized design. The distance between adjacent microlens is 300μm, and each microlens corresponds to the sky area of 1. 5″. The received light is incorporated into the corresponding fiber core with the focal ratio F/8. 2. The relationship between fiber core diameter and spectral resolution of the spectrometer is analyzed systematically. The design specifications of the fiber are 35/ 105/125μm. This parameter can not only meet the requirements of the optical fiber to receive all the optical information transmitted by the microlens but also can obtain the spectral resolution and relatively short slit width to meet the system’s requirements. The influence of fiber diameter and micro-hole depth on the actual incidence focal ratio of the IFU array is quantitatively analyzed, and the micro-hole size is selected as 130μm in diameter and 3mm in depth. A two-dimensional arrayed optical fiber is reorganized at the pseudoslit end, and the optical information is imported into the spectrometer in a linear arrangement. The distance between adjacent fibers is 130μm. The problem of IFU fiber fixation and polishing is solved. The average energy transmission efficiency of IFU is 77. 7%, and the RMS is 1. 6%. All fiber output focal ratio EE90is slower than F/7. The RMS value of the lateral(alignment)offset of the IFU pseudo-slit end fiber is less than 2. 7μm, and the RMS value of the longitudinal(perpendicular to alignment)offset is less than 1. 8μm. After the installation and debugging of IFU and FASOT-1Bsystems, the confirmatory observation was carried out, and the Stokes spectrum of the MgI chromosphere in the solar NOAA12738active region was successfully obtained. This IFU has also become the first fiber plus convex lens IFU independently developed and applied to scientific observation in China.</p>
摘要: <p>三维成谱成像技术是一种能够对观测视场中的所有展源目标进行实时光谱获取的技术,它可以通过单次采样同时获得目标光谱域和二维空间域信息。光纤积分视场单元(IFU)则是天文三维成谱成像技术的关键器件,通过将接收的像面切分,将像面信息细分到若干单元传递至光谱仪,在此过程中二维的展源目标被重整为互不干扰的线性排列供光谱仪进行采样提取,能有效提高天文观测的时间分辨率。介绍一种具有242光纤单元的IFU,该IFU目前应用于中科院云南天文台的光纤阵列太阳光学望远镜(型号FASOT-1B)系统。为满足FASOT-1B的指标要求,获得高传输效率、高光谱分辨率和高时间分辨率观测效果,该IFU采用微透镜阵列加光纤阵列的结构,该微透镜为正六边形球面镜,实现接近100%的空间填充率。综合考虑光纤积分视场单元前置望远镜系统和后端光谱仪系统的设计参数,优化设计了一对11×11的微透镜阵列,相邻微透镜间距300μm,每个微透镜对应天区1.5″,以焦比F/8.2将接收到的光汇入与其对应的光纤纤芯中。系统分析光纤芯径与光谱仪光谱分辨率间的关系,设计的光纤规格为:35/105/125μm,该设计既能满足光纤接收微透镜所传递的全部光信息,同样可以得到系统需求的光谱分辨率和相对短的狭缝宽度。量化分析IFU阵列端光纤直径与微微孔深度对光纤实际入射焦比的影响,选定的微孔尺寸直径130μm,深3 mm。阵列端二维排布的光纤在赝狭缝端经过重整,以线性排列将光信息导入光谱仪,相邻光纤间距130μm。整个IFU的能量传输效率均值77.7%,波动值RMS 1.6%;所有光纤出射焦比EE90均慢于F/7。IFU出射端(赝狭缝端)光纤横向(排列方向)偏移量RMS值小于2.7μm,纵向(垂直于排列方向)偏移量RMS值小于1.8μm。FASOT-1B系统安装IFU并调试后进行了验证性观测,成功获取了太阳NOAA12738活动区MgI色球的斯托克斯光谱,该IFU也成为国内首个自主研制并应用于科学观测的光纤加微透镜型IFU。 </p>
2023-04-24T03:02:51Z
Dual-beam polarimeter based on nonachromatic wave plates with high polarimetric efficiency over a broad band
Wan F(万凡)
Zhong Y(钟悦)
Qu ZQ(屈中权)
Xu Z(徐稚)
Zhang H(张辉)
http://ir.ynao.ac.cn:80/handle/114a53/25892
2023-06-05T05:19:55Z
2023-04-24T02:53:23Z
题名: Dual-beam polarimeter based on nonachromatic wave plates with high polarimetric efficiency over a broad band
作者: Wan F(万凡); Zhong Y(钟悦); Qu ZQ(屈中权); Xu Z(徐稚); Zhang H(张辉)
摘要: <p>The design and test of a dual-beam polarimeter to be applied to the Fiber Array Solar Optical Telescope of the second generation is described. The polarimeter consists of a half and a quarter nonachromatic wave plate, followed by a polarizing beam splitter as a polarization analyzer. It has the features of simple structure, stable operation, and temperature insensitivity. The most outstanding feature of the polarimeter is that a combination of commercial nonachromatic wave plates is used as a modulator to have the high polarimetric efficiency of the Stokes polarization parameters over 500–900 nm; the efficiency balance among the linear and circular polarization parameters is also taken into account. In order to see the stability and reliability of this polarimeter, we perform the actual measurement of the polarimetric efficiencies of the assembling polarimeter in the laboratory. It is found that the lowest linear polarimetric efficiency is over 0.46, the lowest circular polarimetric efficiency is above 0.47, and the total polarimetric efficiency is greater than 0.93 over 500–900 nm. The measured results are basically consistent with the theoretical design. Thus, the polarimeter guarantees observers to choose freely spectral lines, formed in different layers of the solar atmosphere. It can be concluded that such a dual-beam polarimeter based on nonachromatic wave plates has excellent performance and can be extensively applied in astronomical measurement. © 2023 Optica Publishing Group.</p>
2023-04-24T02:53:23Z
基于连续旋转波片调制的傅里叶解调方法研究
林哲宇
徐稚
http://ir.ynao.ac.cn:80/handle/114a53/25864
2023-09-09T18:00:13Z
2023-03-20T05:14:16Z
题名: 基于连续旋转波片调制的傅里叶解调方法研究
作者: 林哲宇; 徐稚
摘要: <p>Continuously rotating waveplates as the polarization modulator is an important configuration which is widely adopted in many ground⁃based or space⁃based solar telescopes for the solar magnetic field measurement. In this paper, we present the derivation and formula of the Fourier demodulation in the context of continuously rotating waveplates. We testify the formula correctness by using the synthetic FeI Stokes profiles, which are produced by the RH radiative transfer code with a given atmosphere model. In addition, we calculate the effect of the home⁃position errors, the positioning errors of the waveplate rotation and the time difference between the waveplate slot time and the detector frame time on the demodulated results by using the demodulation matrix and the Fourier analysis. The main findings are: (1) The new Fourier analysis can provide more accurate results than the simple one adopted by the step⁃wise modulation. Similar results are obtained when we do the relative error estimation using these two demodulation methods. (2) Considering the relative errors due to the home⁃position angle error, we find the demodulated linear polarization are almost the same using these two methods. However, in the case of circular polarization, the demodulation based on the demodulation matrix is more reliable. No matter which method is applied, it is shown that the home⁃position angle error has the same effect on both circular and linear polarization. The relative error of 10-3 requires the home⁃position angle accuracy within ten arc seconds. (3) Calculating the relative error caused by the position error of the waveplate rotation, we find the demodulation results are almost equal using these two methods. Both show that the position error has more influence on the linear polarization. Furthermore, the requirements of the position accuracy are much higher (ten of arc seconds) than that in the case of step⁃wise modulation (0. 1 degree) in order to achieve the relative error of 10-3. (4) It is crucial to precisely match the detector frame time and the waveplate rotation slot time. We investigate the relative error due to the difference between them and find that the time difference (Δ) can cause cross⁃talk between the linear polarization signals. It has more prominent effect on the linear polarization than on the circular polarization. The time difference as a percent of the waveplate slot time (Δ/ T) is required to be smaller than 1% if the relative error is smaller than 10-3 for the linear polarization.</p>
摘要: <p>给出了在连续式旋转波片调制模式下傅里叶分析的推导过程和解调公式,并利用理论偏振轮廓对公式的准确性进行了验证。分别采用傅里叶分析和解调矩阵两种解调方法定量模拟了在连续式调制模式下波片的初始方位角误差、旋转定位误差以及探测器曝光过程中时间差占比3个因素对测量精度的影响。主要结论有(1)简单的傅里叶分析不再适用于连续式调制的结果解调,文中给出的新傅里叶分析方法与解调矩阵方法在进行误差分析时,可以得到基本一致的结果。(2)考虑初始方位角误差引起的影响,我们发现对于线偏振信号来说,采用傅里叶分析和解调矩阵可以得到非常一致的结果,而对于圆偏振来说,基于解调矩阵的方法得到的结果误差相对较小。但是两种解调方法都反映了初始方位角误差对圆偏振和线偏振产生的影响一致,且相对误差的大小与偏振信号本身的强弱有关。初始方位角的误差要求在十几角秒量级才能满足结果的相对误差在10-3以下。(3)考虑旋转定位误差引起的影响时发现,采用傅里叶分析和解调矩阵得到的结果非常接近。两者同时显示出旋转定位误差对线偏振信号造成的影响更为明显,且相对误差的大小与信号的强弱有关。当波片的重复定位精度在10″左右时,对10-2量级的弱偏振信号来说,测量误差也能在10-3量级左右。从这一点上,我们发现连续式调制模式对波片旋转的定位精度要求要明显高于步进式调制模式。(4)两种解调方法的结果均显示,在连续式调制模式下,波片的调制周期与探测器曝光时长的时间差(Δ)会造成线偏振信号之间的串扰,即时间差占比(Δ/T)对线偏振信号造成的影响比对圆偏振信号的影响更为明显。当Δ/T小于1%时,线偏振信号相对误差达到10-3量级。 </p>
2023-03-20T05:14:16Z
The Decay Process of an alpha-configuration Sunspot
Peng Y(彭洋)
Xue ZK(薛志科)
Yan XL(闫晓理)
Norton, Aimee A.
Qu ZQ(屈中权)
Wang JC(王金成)
Xu Z(徐喆)
Yang LH(杨丽恒)
Li, Qiao-Ling
Yang LP(杨丽平)
Sun X(孙霞)
http://ir.ynao.ac.cn:80/handle/114a53/25816
2024-03-26T05:25:07Z
2023-02-13T02:22:40Z
题名: The Decay Process of an alpha-configuration Sunspot
作者: Peng Y(彭洋); Xue ZK(薛志科); Yan XL(闫晓理); Norton, Aimee A.; Qu ZQ(屈中权); Wang JC(王金成); Xu Z(徐喆); Yang LH(杨丽恒); Li, Qiao-Ling; Yang LP(杨丽平); Sun X(孙霞)
摘要: <p>The decay of sunspot plays a key role in magnetic flux transportation in solar active regions (ARs). To better understand the physical mechanism of the entire decay process of a sunspot, an alpha-configuration sunspot in AR NOAA 12411 was studied. Based on the continuum intensity images and vector magnetic field data with stray light correction from Solar Dynamics Observatory/Helioseismic and Magnetic Imager, the area, vector magnetic field and magnetic flux in the umbra and penumbra are calculated with time, respectively. Our main results are as follows: (1) The decay curves of the sunspot area in its umbra, penumbra, and whole sunspot take the appearance of Gaussian profiles. The area decay rates of the umbra, penumbra and whole sunspot are -1.56 MSH day(-1), -12.61 MSH day(-1) and -14.04 MSH day(-1), respectively; (2) With the decay of the sunspot, the total magnetic field strength and the vertical component of the penumbra increase, and the magnetic field of the penumbra becomes more vertical. Meanwhile, the total magnetic field strength and vertical magnetic field strength for the umbra decrease, and the inclination angle changes slightly with an average value of about 20 degrees; (3) The magnetic flux decay curves of the sunspot in its umbra, penumbra, and whole sunspot exhibit quadratic patterns, their magnetic flux decay rates of the umbra, penumbra and whole sunspot are -9.84 x 10(19) Mx day(-1), -1.59 x 10(20) Mx day(-1) and -2.60 x 10(20) Mx day(-1), respectively. The observation suggests that the penumbra may be transformed into the umbra, resulting in the increase of the average vertical magnetic field strength and the reduction of the inclination angle in the penumbra during the decay of the sunspot.</p>
2023-02-13T02:22:40Z
光纤阵列太阳光学望远镜(FASOT)机械系统研究和设计
李少英
http://ir.ynao.ac.cn:80/handle/114a53/25792
2023-02-13T03:06:31Z
2023-02-06T05:32:22Z
题名: 光纤阵列太阳光学望远镜(FASOT)机械系统研究和设计
作者: 李少英
摘要: High-precision polarization spectral imaging obtained by the fiber array solar optical telescope (FASOT) will reveal the physical parameter structure of several levels in photosphere and chromosphere, and the principle of the transfer of magnetic field and energy from the bottom of the photosphere through the temperature minimum region, the bottom layer of the chromosphere and the middle and upper layers to the corona will be understood, so as to serve the prediction of solar activity and space disaster weather. Based on the scientific needs and key technique of FASOT, this paper is focused on the mechanical structure of the key componets of the FASOT telescope, and detail the analysis and design is presented.The optimization design and rigidity improvement of the mechanical structure of the telescope directly affect the bending deformation of the mechanical structure, the reasonable layout and use of structural materials and weight. The heat distribution of the key structure of the telescope will directly affect the thermal deformation and working performance of the structure, so as to directly affect the observation quality. Based on the lightweight requirement of telescope structure and the constant temperature working requirement of key parts, the key technologies of lightweight optimization design of telescope cylindrical structure and non cylindrical structure, heat distribution and optimization design of key parts were studied as follows in order to reduce the bending deformation and thermal influence of the telescope and ensure the normal accuracy and working performance of the telescope:Using three-dimensional modeling software SOLIDWORKS and finite element software, genetic algorithm optimization is used to optimize the tubes with different ribs and different internal diameters. In case of the tube, it has to be subject to its own gravity and the end is subject to an indefinite bending force, through the analysis of the structure optimization results, it is obtained that under the same deformation, the axial length of the optimized rib should be more than 50% of the tube length, while the optimized rib takes form of the trapezoid; The tube with two ribs is the heaviest; When the number of ribs becomes greater than or equal to 4, the weight of the optimized tube tends to be stable; the weight of the optimized tube with 4 trapezoidal ribs and a flange is 15.8-73.2% lighter than other optimized tube structure. The effectiveness of the tube simulation model is verified by experiments. Based on the theoretical analysis of tubes with and without ribs, a new formula is proposed to predict which kind of tube with or without ribs has high stiffness. The simulation results of the tube model are consistent with the analytic results of the formula. Through the optimization and comparison of tubes with different shapes, the optimized tube with four trapezoidal ribs and one flange ranks the lightest. The new formula and new optimized tube layout will be used for the optimal design of the tube of the telescope and other equipment.According to the characteristics and applicable conditions of topology optimization and genetic algorithm, the design route and method of joint optimization of topology optimization and genetic algorithm are obtained. Joint optimization of topology optimization and genetic algorithm for a specific wheel structure in the telescope has reduced the weight of the wheel structure by 53.6%. The technical route of joint optimization of topology optimization and genetic algorithm will be used for the optimal design of telescope structure or other solid structures, so as to reduce the waste of resources and provide reference for sustainable development technology.Polarization measurement is the key to obtain the information of the solar atmospheric magnetic field, and its measurement accuracy depends on the measurement accuracy of the delay measurement of the polarization measurement element, while the measurement accuracy of the delay measurement depends on the temperature control of the polarization measurement element. According to the working requirements of ferroelectric liquid crystal (FLC) and liquid-crystal variable-retarder (LCVR) polarizers in polarization analyzer, a multifunctional incubator is designed. The structure of the incubator is optimized by finite element analysis, the influence of ambient temperature and target temperature on the thermostatic accuracy of the incubator is analyzed, the relationship between them is put forward, and the reliability of their relationship is verified by experiments. According to this relationship, a new method to improve the accuracy of the incubator has been proposed, and thus the structure of the incubator is optimized by this new method. When the incubator is set to be at − 10 ° C, the temperature fluctuation of the small incubator box was 0.000014 ° C. Compared with the ultra precision three-coordinate measuring machine, the target temperature fluctuation of the incubator is reduced by more than 98.6% and more than 99.72% compared with the molecular measuring machine. This method can greatly improve the thermostatic accuracy of the incubator.The temperature structure of FLC and LCVR in FASOT telescope is optimized. It is found that the temperature distribution of the insulated optical elements can meet the requirement of temperature accuracy when the end of the extended insulation structure is completely closed.
摘要: 通过光纤阵列太阳光学望远镜(FASOT)获得的高精度偏振成谱成像的资料分析,来揭示光球和色球中几个层次的物理参量结构,了解磁场和物质能量从光球底层经过色球底层、中高层和温度极小区传输至日冕的原理,以服务于太阳的活动和空间灾害天气的预报。本文根据科学需要着重深入研究了FASOT望远镜机械系统结构需要解决的关键问题并给出分析设计。望远镜机械结构轻量化优化设计和刚性的提高,直接影响了机械结构的弯曲变形、结构材料和重量的合理布局及使用,望远镜关键结构的热量分布直接会影响结构的热变形和工作性能,从而直接影响观测质量。本文基于望远镜结构轻量化要求和关键部分恒温工作要求,对望远镜筒状结构和非筒状结构轻量化优化设计、望远镜的热分布和关键部分优化设计的关键技术进行了如下研究,以利于减少望远镜的弯曲变形和热影响,保证望远镜的正常精度和工作性能:采用三维建模软件SOLIDWORKS和有限元软件进行遗传算法优化,尤其是对不同筋数和不同内径的筒状结构进行优化。在筒状结构受自身重力和末端受到方向不定弯曲力情况下,通过对结构优化结果的分析,得到在保持相同的变形下,优化加强筋的轴向长度是筒状结构长的50% 以上,同时优化的加强筋外形结构为梯形;带有两个加强筋的筒状结构最重;加强筋的数量大于等于4个以后,优化筒状结构的重量趋于稳定值;带有4个梯形加强筋和一个法兰的优化筒状结构的重量比已有研究了的优化筒状结构轻 15.8-73.2%。用实验验证了筒状结构仿真模型的有效性。根据对带有1个加强筋和没带加强筋的圆筒状结构的理论分析提出了一种新的提高筒状结构抗弯刚度合适宽厚的加强筋公式,来预测有加强筋与没加强筋筒状结构中哪种筒状结构刚度高。此公式经对筒状结构模型的仿真得到的结果与公式分析结果一致。经过对不同形状的筒状结构进行优化和比较,发现带有四个梯形筋和一个法兰的优化筒状结构最轻。以上所得到提高筒状结构抗弯刚度合适宽厚的加强筋公式和优化的筒状结构布局可用于望远镜涉及到筒状结构和其它设备上筒状结构的优化设计。根据拓扑优化和遗传算法的特点和适用条件提出了拓扑优化和遗传算法联合优化的设计路线和方法。对望远镜中一个具体的轮状结构进行了拓扑优化和遗传算法联合优化,使轮状结构的重量减轻了53.6%。拓扑优化和遗传算法联合优化的技术方法路线可以用于望远镜结构或其它实体结构的优化设计,以减少资源的浪费和为可持续发展技术提供参考。偏振测量是获取太阳大气磁场信息的关键,其测量精度依赖于偏振测量元件延迟量测量精度,而延迟量的测量精度依赖于偏振测量元件的温度控制。本文根据望远镜中的关键部分一偏振分析器中的铁电液晶 (FLC) 和液晶相位延迟器 (LCVR)的工作环境要求,设计了一种多功能恒温箱。对恒温箱的结构采用有限元进行优化,并分析环境温度与目标温度对恒温箱恒温精度的影响,给出了它们之间的关系式,并用实验验证了它们之间的关系可靠性。并根据此关系式提出了提高恒温箱温控精度的新方法,采用此新方法优化设计了恒温箱结构。在−10°C环境温度下,小恒温箱盒子的温度波动为0.000014°C,与超精密三坐标测量机相比,该恒温箱的目标温度波动值降低了98.6%以上,与分子测量机相比降低了99.72%以上。此方法可以大大提高恒温箱的恒温控制精度。对FLC和LCVR在FASOT望远镜中的恒温结构进行优化,发现当保温层加长结构末端全封闭时,被保温光学元件的温度分布才能满足恒温精度要求。
2023-02-06T05:32:22Z