白光日冕仪杂散光抑制的关键技术研究
发布时间：2019-01-08 12:49
【摘要】：日冕是太阳大气的最外层,从色球边缘向外延伸到几个太阳半径处,广义上的日冕范围甚至包括地球周围的空间环境。剧烈的日冕活动(太阳风、日冕物质抛射等)严重影响日地空间环境。日冕仪是用于非日食情况下,对太阳日冕以及日冕抛射现象进行实时观测的光学仪器。本文以夸父计划中白光日冕仪的技术指标为基础,设计并完成了国内首台外掩式白光日冕仪原理演示样机。以此原理演示样机为基础,进行了外掩式白光日冕仪杂散光抑制关键技术的研究。日冕仪原理演示样机的主要参数如下:视场为±2.5-15 R⊙(R⊙表示一个太阳半径,约为16’),口径为30mm,有效焦距200mm,分辨率为14sec/pixel,工作波段为650-750nm。相比太阳光球层的亮度,日冕光的亮度极其微弱,因此日冕仪杂散光抑制是日冕仪系统的关键问题。日冕仪杂散光根据形成机理不同行大致分为五类:太阳直射光;系统光孔的衍射光;物镜表面二次反射光;透镜加工精度所引起的杂散光;玻璃材料本身缺陷等引起的杂散光。本文首先对这五类杂散光产生的主要原因进行理论分析,这里应用分数傅里叶变换理论分析了外掩体边缘衍射光能量,并通过ASAP软件建模分析了物镜表面二次反射形成鬼像杂散光的机理。然后,论文中针对各级杂散光形成机理的不同,分别提出了相应的抑制方法,使用Trace Pro软件,针对拒热镜对太阳直射光的抑制,视场光阑对外窗口边缘衍射光遮拦,以及内掩体对外掩体边缘衍射光的遮拦进行了模拟分析。此外,论文还就外掩式日冕仪内视场渐晕的问题进行了理论分析和计算机模拟,得到了日冕仪渐晕随视场变化的规律,并模拟出二维等晕图。为了对日冕仪杂散光抑制有更深入的研究,根据理论部分提出的日冕仪杂散光分级抑制的方法,设计相对应的实验,观测各级杂散光的抑制情况。实验结果显示日冕仪各级杂散光抑制的方法切实有效,杂散光得到了很好的抑制。最后,本文对外掩式日冕仪原理演示样机杂散光抑制整体水平进行检测,总体杂散光抑制水平可以达到10-9 B⊙量级(其中B⊙代表太阳光球层平均亮度)。
[Abstract]:The corona is the outermost layer of the solar atmosphere, extending from the edge of the chromosphere to several solar radii. In a broad sense, the coronal range even includes the space environment around the earth. Intense coronal activity (solar wind, coronal mass ejection, etc.) seriously affects the solar-terrestrial space environment. Coronal apparatus is an optical instrument for real-time observation of the solar corona and its ejection in the case of non-solar eclipse. Based on the technical specifications of the white corona apparatus in the Kuafa project, the principle demonstration prototype of the first mask white corona apparatus in China has been designed and completed in this paper. Based on the principle demonstration prototype, the key technology of stray light suppression of the white coronal apparatus is studied. The main parameters of the prototype are as follows: the field of view is 卤2.5-15R _ (-) (R _ denote a solar radius, about 16'), the aperture is 30 mm, the effective focal length is 200 mm, the resolution is 14 sec-p pixel, and the working band is 650-750 nm. Compared with the brightness of the solar photosphere, the brightness of the coronal light is very weak, so the suppression of stray light is the key problem in the coronal system. Coronal instrument stray light is divided into five categories according to its formation mechanism: direct solar light; diffraction light from the system aperture; secondary reflection light from the surface of the objective lens; stray light caused by the machining accuracy of the lens; and the stray light caused by the defects of the glass material itself. In this paper, the main causes of these five kinds of stray light are analyzed theoretically. Here, the energy of diffractive light at the edge of the outer mask is analyzed by using the fractional Fourier transform theory. The mechanism of the secondary reflection of the objective lens is analyzed by ASAP software. Then, aiming at the different formation mechanism of stray light at different levels, the corresponding suppression methods are put forward in this paper. By using Trace Pro software, aiming at the suppression of direct solar light by the thermal rejection mirror, the diffraction light of the external window of the field of view aperture is shaded. And the external mask edge diffractive light is simulated and analyzed. In addition, theoretical analysis and computer simulation are carried out on the camouflage of the camouflage in the coronal instrument. The variation of the camber with the field of view is obtained, and the 2-D isohalo pattern is simulated. In order to study the suppression of stray light in coronal instrument more deeply, according to the method of hierarchical suppression of stray light proposed in the theoretical part, a corresponding experiment was designed to observe the suppression of stray light at all levels. The experimental results show that the method of suppression of stray light at all levels of the coronal apparatus is effective and the stray light is well suppressed. Finally, the principle of the external mask coronal apparatus is used to demonstrate the whole level of stray light suppression of the prototype. The total stray light suppression level can reach 10 ~ (-9) B ~ (-) (where B _ (?) represents the average brightness of the solar photosphere).
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P111.41
本文编号：2404622
[Abstract]:The corona is the outermost layer of the solar atmosphere, extending from the edge of the chromosphere to several solar radii. In a broad sense, the coronal range even includes the space environment around the earth. Intense coronal activity (solar wind, coronal mass ejection, etc.) seriously affects the solar-terrestrial space environment. Coronal apparatus is an optical instrument for real-time observation of the solar corona and its ejection in the case of non-solar eclipse. Based on the technical specifications of the white corona apparatus in the Kuafa project, the principle demonstration prototype of the first mask white corona apparatus in China has been designed and completed in this paper. Based on the principle demonstration prototype, the key technology of stray light suppression of the white coronal apparatus is studied. The main parameters of the prototype are as follows: the field of view is 卤2.5-15R _ (-) (R _ denote a solar radius, about 16'), the aperture is 30 mm, the effective focal length is 200 mm, the resolution is 14 sec-p pixel, and the working band is 650-750 nm. Compared with the brightness of the solar photosphere, the brightness of the coronal light is very weak, so the suppression of stray light is the key problem in the coronal system. Coronal instrument stray light is divided into five categories according to its formation mechanism: direct solar light; diffraction light from the system aperture; secondary reflection light from the surface of the objective lens; stray light caused by the machining accuracy of the lens; and the stray light caused by the defects of the glass material itself. In this paper, the main causes of these five kinds of stray light are analyzed theoretically. Here, the energy of diffractive light at the edge of the outer mask is analyzed by using the fractional Fourier transform theory. The mechanism of the secondary reflection of the objective lens is analyzed by ASAP software. Then, aiming at the different formation mechanism of stray light at different levels, the corresponding suppression methods are put forward in this paper. By using Trace Pro software, aiming at the suppression of direct solar light by the thermal rejection mirror, the diffraction light of the external window of the field of view aperture is shaded. And the external mask edge diffractive light is simulated and analyzed. In addition, theoretical analysis and computer simulation are carried out on the camouflage of the camouflage in the coronal instrument. The variation of the camber with the field of view is obtained, and the 2-D isohalo pattern is simulated. In order to study the suppression of stray light in coronal instrument more deeply, according to the method of hierarchical suppression of stray light proposed in the theoretical part, a corresponding experiment was designed to observe the suppression of stray light at all levels. The experimental results show that the method of suppression of stray light at all levels of the coronal apparatus is effective and the stray light is well suppressed. Finally, the principle of the external mask coronal apparatus is used to demonstrate the whole level of stray light suppression of the prototype. The total stray light suppression level can reach 10 ~ (-9) B ~ (-) (where B _ (?) represents the average brightness of the solar photosphere).
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P111.41
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相关期刊论文 前5条
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，本文编号：2404622
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