分类： 天文学 >> 天文仪器与技术 提交时间： 2024-04-18 合作期刊: 《天文技术与仪器（英文）》
摘要：Radioheliographs can obtain solar images at high temporal and spatial resolution, with a high dynamic range. These are among the most important instruments for studying solar radio bursts, understanding solar eruption events, and conducting space weather forecasting. This study aims to explore the effective use of radioheliographs for solar observations, specifically for imaging coronal mass ejections (CME), to track their evolution and provide space weather warnings. We have developed an imaging simulation program based on the principle of aperture synthesis imaging, covering the entire data processing flow from antenna configuration to dirty map generation. For grid processing, we propose an improved non-uniform fast Fourier transform (NUFFT) method to provide superior image quality. Using simulated imaging of radio coronal mass ejections, we provide practical recommendations for the performance of radioheliographs. This study provides important support for the validation and calibration of radioheliograph data processing, and is expected to profoundly enhance our understanding of solar activities.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Ruisheng Zheng
Liang Zhang
Bing Wang
Xiangliang Kong
Hongqiang Song
Zhao Wu
Shiwei Feng
Huadong Chen
Yao Chen
摘要： Compound eruptions represent that multiple closely spaced magnetic structures erupt consecutively within a short interval, and then lead to a single flare and a single CME. However, it is still subtle for the links between multiple eruptions and the associated single flare or/and single CME. In this Letter, we report the compound eruptions of twin close flux ropes (FR1 and FR2) within a few minutes that resulted in a flare with a single soft X-ray peak and a CME with two cores. The successive groups of expanding loops and double peaks of intensity flux in AIA cool wavelengths indicate two episodes of internal magnetic reconnections during the compound eruptions. Following the eruption of FR2, the erupting FR1 was accelerated, and then the expanding loops overlying FR2 were deflected. Moreover, the eruption of FR2 likely involved the external magnetic reconnection between the bottom of the overlying stretching field lines and the rebounding loops that were previously pushed by the eruption of FR1, which was evidenced by a pair of groups of newly-formed loops. All results suggest that the compound eruptions involved both internal and external magnetic reconnections, and two erupting structures of twin FRs interacted at the initial stage. We propose that two episodes of internal magnetic reconnections were likely united within a few minutes to form the continuous impulsive phase of the single peaked flare, and two separated cores of the CME was possibly because that the latter core was too slow to merge with the former one.
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