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arXiv 2410.16637astro-ph.SR
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用于全球日冕诊断的多狭缝极紫外光谱仪的光学优化

Optical optimization of a multi-slit extreme ultraviolet spectrograph for global solar corona diagnostics

Yufei Feng, Xianyong Bai, Sifan Guo, Hui Tian, Lami Chan, Yuanyong Deng, Qi Yang, Wei Duan, Xiaoming Zhu, Xiao Yang, Zhiwei Feng, Zhiyong Zhang

AI总结:

本文提出一种五狭缝极紫外成像光谱仪设计,通过优化多层膜结构和光学参数,在18.3–19.8 nm波段实现全球日冕高时间分辨率光谱诊断,全盘扫描约5分钟,光谱分辨本领大于1461。

摘要:

太阳外层大气日冕等离子体参数在全球尺度上的时空演化,来源于极紫外波段太阳全盘成像光谱观测,对于理解和预报太阳爆发至关重要。我们提出了一种用于全球日冕诊断的高时间分辨率多狭缝极紫外成像光谱仪,并给出了18.3至19.8 nm波长范围的初步仪器设计。该仪器采用综合方法获取全球日冕的空间和光谱信息,提高探测时间分辨率并避免光谱重叠。我们首先描述了光学特性与结构参数之间的关系,特别是光谱重叠与狭缝数量之间的关系,并给出了一般性的多狭缝极紫外成像光谱仪设计流程。对多层膜结构进行了优化,以增强观测波段内的有效面积。设置了五条相距较远的狭缝来划分整个太阳视场,相对于单狭缝,将太阳盘面光栅扫描的时间分辨率提高了5倍。孔径直径为150 mm的光学系统的光谱分辨本领被优化至大于1461。沿狭缝方向和扫描方向的空间分辨率分别约为4.4角秒和6.86角秒。对Al/Mo/B4C多层膜结构进行了优化,峰值有效面积在19.3 nm处约为1.60 cm²,半高全宽约为1.3 nm。完成全盘光栅扫描的时间分辨率约为5分钟。最后,通过系统光子预算的端到端计算以及观测图像和光谱的模拟,对仪器性能进行了评估。我们的研究表明,该方法在全球日冕等离子体诊断方面具有广阔前景。

英文摘要:

The spatial-temporal evolution of coronal plasma parameters of the solar outer atmosphere at global scales, derived from solar full-disk imaging spectroscopic observation in the extreme-ultraviolet band, is critical for understanding and forecasting solar eruptions. We propose a multi-slits extreme ultraviolet imaging spectrograph for global coronal diagnostics with high cadence and present the preliminary instrument designs for the wavelength range from 18.3 to 19.8 nm. The instrument takes a comprehensive approach to obtain global coronal spatial and spectral information, improve the detected cadence and avoid overlapping. We first describe the relationship between optical properties and structural parameters, especially the relationship between the overlapping and the number of slits, and give a general multi-slits extreme-ultraviolet imaging spectrograph design process. Themultilayer structure is optimized to enhance the effective areas in the observation band. Five distantly-separated slits are set to divide the entire solar field of view, which increase the cadence for raster scanning the solar disk by 5 times relative to a single slit. The spectral resolving power of the optical system with an aperture diameter of 150 mm are optimized to be greater than 1461. The spatial resolution along the slits direction and the scanning direction are about 4.4''and 6.86'', respectively. The Al/Mo/B4C multilayer structure is optimized and the peak effective area is about 1.60 cm2 at 19.3 nm with a full width at half maximum of about 1.3 nm. The cadence to finish full-disk raster scan is about 5 minutes. Finally, the instrument performance is evaluated by an end-to-end calculation of the system photon budget and a simulation of the observational image and spectra. Our investigation shows that this approach is promising for global coronal plasma diagnostics.

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