大视场日冕仪关键技术研究

发布时间：2019-04-23 12:33

【摘要】：日冕仪是观测日冕和日冕物质抛射现象的仪器。观测日冕和日冕物质抛射现象可以研究太阳磁场对地球的影响，并可以对影响地球及日地空间的灾害性空间天气进行预警。本论文论及的大视场日冕仪是国际上首次设计的中心遮拦的大视场日冕仪，国际上报道的中心遮拦的日冕仪最大视场为30R⊙（R⊙为太阳半径），大视场日冕仪在近地点的视场为72R⊙，在远地点的视场达到215R⊙，可以对太阳到地球范围内的日冕及日冕物质抛射现象进行观测。本论文借鉴国际上日冕仪研制的经验，对日冕仪进行设计。本论文研制的大视场日冕仪光学系统主要参数为：视场为以太阳为中心±20度，像素分辨率为1.2arcmin，像素大小为13.5μm，波段为630nm～730nm，系统总长为896mm，其中光学系统总长为356mm，工作F数为5，像方焦距为40mm，传递函数大于0.65。本论文研制的日冕仪由于视场远大于国际上现有的日冕仪，增加了日冕仪对杂散光抑制的要求。为此对日冕仪的杂散光抑制进行了深入研究。首先从理论上对日冕仪外掩体和外窗口的衍射杂散光水平进行了计算。其次，对大视场日冕仪的衍射杂散光和散射杂散光分别进行建模，，得到理论上杂散光的量级。衍射杂散光建模主要应用分数傅立叶变换理论和菲涅耳——基尔霍夫衍射积分理论，散射杂散光建模主要应用ABC模型，对表面粗糙度和灰尘污染物造成的杂散光进行计算。最后，本文对大视场日冕仪所有可能产生的杂散光进行分级，并对其分别进行抑制。其中一级为太阳直射光；二级为外掩体和外窗口的衍射光；三级为物镜口径的衍射光，物镜表面粗糙度和灰尘造成的散射光，拒热镜表面散射的杂散光和物镜表面多次反射造成杂散光。最后对日冕仪整机杂散光进行检测，总杂散光抑制水平达到10-11B⊙量级（B⊙为太阳平均亮度）。
[Abstract]:Corona is an instrument for observing coronal and coronal mass ejections. Observation of coronal and coronal mass ejections can be used to study the influence of solar magnetic field on the earth and early warning of disastrous space weather affecting the earth and solar-terrestrial space. The large-field coronation instrument discussed in this paper is the first designed in the world, and the maximum field of view of the center-occluded coronation instrument reported by the international report is 30R? The coronal and coronal mass ejections from the sun to the earth can be observed at the perigee and apogee by the large field of view coronograph (72R) and the apogee (215R). The coronal and coronal mass ejections from the sun to the earth can be observed in the range of the sun to the earth. This paper draws lessons from the experience of international coronal instrument development, and designs the coronal instrument. The main parameters of the optical system developed in this paper are as follows: the field of view is at the center of the sun 卤20 degrees, the pixel resolution is 1.2 arcmin, the pixel size is 13.5 渭 m, the band is 630nm and 730nm, and the total length of the system is 896mm. The optical system has a total length of 356 mm, a working F number of 5, a square focal length of 40 mm and a transfer function of more than 0.65. Since the field of view of the coronal instrument developed in this paper is much larger than that of the existing coronal instrument in the world, the requirements of the coronal instrument for the suppression of stray light are increased. In this paper, the stray light suppression of the corona instrument is deeply studied. Firstly, the diffractive stray light level of the corona's outer bunker and outer window is calculated theoretically. Secondly, the diffractive stray light and scattered stray light of the large field corona instrument are modeled, and the order of stray light is obtained theoretically. The fractional Fourier transform theory and Fresnel-Kirchhoff diffraction integral theory are used in the modeling of diffracted stray light. The ABC model is mainly used to calculate the surface roughness and stray light caused by dust contaminants. Finally, in this paper, all possible stray light generated by the large field corona meter is graded, and the stray light is suppressed separately. The first is the direct solar light, the second is the diffracted light of the outer bunker and the outer window. The third order is the diffracted light of the aperture of the objective lens, the scattered light caused by the roughness of the surface of the objective lens and dust, the stray light scattered from the surface of the heat repellent lens and the spurious light caused by the reflection of the surface of the objective lens many times. Finally, the stray light of the corona instrument is detected, and the total stray light suppression level reaches the order of 10? 11B?
【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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