Optical optimization of a dual-band sun-as-a-star extreme ultraviolet spectrograph for measuring the line-of-sight velocity of coronal mass ejections

IF 2.7 3区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

Experimental Astronomy Pub Date : 2025-03-08 DOI:10.1007/s10686-025-09990-y

Sifan Guo, Yufei Feng, Xianyong Bai, Hui Tian, Wei Duan, Xiaoming Zhu, Yajie Chen, Yuanyong Deng, Haiying Zhang, Zhiyong Zhang, Zhiwei Feng, Xiao Yang, Qi Yang, Mohamed Sedik

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引用次数: 0

Abstract

The detection of Line-of-sight (LOS) velocity of coronal mass ejections (CMEs) is crucial for understanding and forecasting their propagation. The LOS velocity can be derived from the Sun-as-a-star extreme ultraviolet spectrograph based on the Doppler effect. However, the poor spectral resolution of existing instruments is not sufficient for detection. In the paper, we propose a dual-band Sun-as-a-star spectrograph with high spectral resolution for measuring the LOS velocity of CMEs. Based on a multilayer concave grating operating in a normal incident mode, we optimized the parameters of the spectrograph for the wavelength ranges of 18.3\( \sim \)21.3 nm and 49.6\( \sim \)52.9 nm. The spectral resolving power for these two ranges exceeds 1000 and 2000, respectively, which is about three times higher than that of the Extreme ultraviolet Variability Experiment onboard the Solar Dynamics Observatory. B\(_4\)C/Al and B\(_4\)C/Mo/Al multilayer structures were optimized to improve the diffraction efficiency across both bands simultaneously. We also evaluated the instrument performance by calculating the photon numbers. Additionally, we discussed the degradation of spectral resolution caused by the stability of satellite platform, determining that the stability should be better than ±7.2\(^{\prime \prime }\)(\( \pm \)0.002\(^\circ \)) within the exposure time of 60 s. Our investigation provides a new way to observe Sun-as-a-star extreme ultraviolet spectrum.

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探测日冕物质抛射（CMEs）的视线速度（LOS）对于了解和预测其传播至关重要。根据多普勒效应，可以从太阳即恒星的极紫外光谱仪中推导出 LOS 速度。然而，现有仪器的光谱分辨率较低，不足以进行探测。本文提出了一种具有高光谱分辨率的双波段日像星摄谱仪，用于测量 CME 的 LOS 速度。基于在正常入射模式下工作的多层凹面光栅，我们优化了波长范围为18.3（\sim \）21.3 nm和49.6（\sim \）52.9 nm的摄谱仪参数。这两个波段的光谱分辨能力分别超过1000和2000，比太阳动力学天文台上的极紫外变异实验的分辨能力高出约三倍。我们对 B\(_4\)C/Al 和 B\(_4\)C/Mo/Al 多层结构进行了优化，以同时提高两个波段的衍射效率。我们还通过计算光子数评估了仪器的性能。此外，我们还讨论了卫星平台稳定性引起的光谱分辨率下降问题，确定在60秒的曝光时间内，稳定性应优于±7.2(^{\prime \prime }\)(\( \pm \)0.002\(^\circ \))。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experimental Astronomy 地学天文-天文与天体物理

CiteScore

5.30

自引率

3.30%

发文量

审稿时长

6-12 weeks

期刊介绍： Many new instruments for observing astronomical objects at a variety of wavelengths have been and are continually being developed. Furthermore, a vast amount of effort is being put into the development of new techniques for data analysis in order to cope with great streams of data collected by these instruments. Experimental Astronomy acts as a medium for the publication of papers of contemporary scientific interest on astrophysical instrumentation and methods necessary for the conduct of astronomy at all wavelength fields. Experimental Astronomy publishes full-length articles, research letters and reviews on developments in detection techniques, instruments, and data analysis and image processing techniques. Occasional special issues are published, giving an in-depth presentation of the instrumentation and/or analysis connected with specific projects, such as satellite experiments or ground-based telescopes, or of specialized techniques.