反射式日冕仪的设计与杂散光分析

发布时间：2018-05-03 11:13

本文选题：拉曼阿尔法 + 光学设计　；参考：《中国科学院研究生院(长春光学精密机械与物理研究所)》2014年博士论文

【摘要】：日冕是太阳大气的最外层，从过渡区顶部向外延伸到几个太阳半径，甚至更远的区域。日冕活动对地球周围空间环境变化影响重大，是空间天气预报的关键部分之一，，对日冕的观测研究对太阳物理学、人类活动乃至对国家经济生活和太阳物理学研究具有重要意义。 Lyman-alpha(拉曼阿尔法)辐射在太阳物理学和日冕物理学中占据了非常重要的地位，作为色球层光谱的主要成分，可以通过拉曼阿尔法光谱的观测分析出色球层的主要结构。对于日冕成像最大的困难是：日冕的亮度相对太阳光球层和色球场而言极为微弱，因此日冕仪的设计需要重点考虑日面照射到仪器上所引起的入瞳边缘衍射和主镜面自身散射的问题。本文首先介绍了日冕仪的发展历史和透射式日冕仪的基本原理，针对外遮光日冕仪的外部遮光器圆盘遮挡效果和边缘衍射光线进行了理论性计算。针对日冕仪反射式结构，提出了入瞳位置假设，并在轴上近似条件下计算了主物镜，次镜和成像反射镜的位置，进一步的计算和讨论了全反射式日冕仪在轴上理想成像近似时，入瞳成像即里奥光阑的位置是场镜和成像镜的焦距与间距的函数；在相同的近似条件下，得到了里奥光阑的尺寸计算公式，是关于三个物镜的焦距和间距的函数，这对以后的全反射日冕仪设计一定的参考价值。设计了口径为40mm、焦距为590mm的全反射式拉曼阿尔法日冕仪，传递函数接近衍射极限。利用光学分析软件建模分析了杂光情况：像面上接收入瞳边缘衍射能量约为入射能量的6.8×10-9，提出主镜面的加工要求。设计并装调一套球面反射式日冕仪实验装置，建立光学分析仿真模型，采用点源透射率PST曲线的方法测量了此日冕仪的杂散光水平，通过对比实际像面上子午面的杂光分布曲线，验证了仿真模型的有效性。最后对比了计算和测量光学系统杂散光的方法，根据杂光系数和PST函数关系式计算得到反射式日冕仪实验装置的杂光系数为0.278。
[Abstract]:The corona is the outermost part of the sun's atmosphere, extending from the top of the transition zone to several solar radii or beyond. Coronal activity has a great influence on the change of space environment around the earth and is one of the key parts of space weather forecast. Human activities and even the study of national economic life and solar physics are of great significance. Lyman-alpha-alpha radiation plays an important role in solar physics and coronal physics. As the main component of chromospheric spectrum, the main structure of chromosphere can be analyzed by the observation of Raman Alpha-alpha spectrum. The biggest difficulty with coronal imaging is that the brightness of the corona is extremely weak relative to the solar sphere layer and the color field. Therefore, the design of coronal instrument should focus on the problems of the diffraction of the entrance pupil edge and the scattering of the main mirror itself caused by the solar surface irradiating to the instrument. In this paper, the development history of coronal apparatus and the basic principle of transmission coronatometer are introduced, and the theoretical calculation of the external shading effect and the edge diffraction light of the external shading coronal apparatus is carried out. In view of the reflective structure of coronal instrument, the assumption of entrance pupil position is put forward, and the positions of primary objective, secondary mirror and imaging mirror are calculated under the condition of axial approximation. The ideal imaging approximation of full reflection coronal instrument on axis is further calculated and discussed. The location of the Leo aperture is a function of the focal length and the spacing of the field mirror and the imaging mirror. Under the same approximate conditions, the calculation formula of the size of the Leo aperture is obtained, which is a function of the focal length and the spacing of the three objective lenses. This will be of reference value to the design of the coronal instrument of total reflection in the future. A full reflection Raman alpha corona instrument with a aperture of 40 mm and focal length of 590mm is designed. The transfer function is close to the diffraction limit. The optical analysis software is used to model and analyze the stray light: the diffraction energy of the edge of the input pupil is about 6.8 脳 10 ~ (-9) of the incident energy on the image plane, and the processing requirements of the main mirror are put forward. A set of experimental apparatus for spherical reflector corona instrument was designed and adjusted, and the optical analysis simulation model was established. The stray light level of the coronal instrument was measured by the method of point source transmittance PST curve. The validity of the simulation model is verified by comparing the distribution curves of the meridian surface on the actual image plane. Finally, the methods of calculating and measuring stray light in optical system are compared. According to the stray light coefficient and PST function formula, the stray light coefficient of the experimental device of reflective coronal apparatus is 0.278.
【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH753.12

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