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arXiv 2403.11652astro-ph.SR
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一系列高能太阳大气事件之前的小尺度磁通量浮现

Small-scale magnetic flux emergence preceding a chain of energetic solar atmospheric events

D. Nóbrega-Siverio, I. Cabello, S. Bose, L. H. M. Rouppe van der Voort, R. Joshi, C. Froment, V. M. J. Henriques

AI总结:

本文利用 SST、IRIS 和 SDO 的高分辨率协同观测,揭示了一次小尺度磁通量浮现事件与随后 Ellerman 炸弹、紫外爆发和喷流等连锁高能事件之间的磁重联因果联系,并强调高分辨率磁图对揭示此类事件真实磁起源的关键作用。

摘要:

仪器技术的进步揭示了太阳大气中大量的小尺度极紫外(EUV)事件。我们的目标是利用高分辨率磁图来详细了解此类现象的磁起源。我们利用瑞典太阳望远镜(SST)、界面区成像光谱仪(IRIS)和太阳动力学天文台(SDO)的协同观测,分析了一次短暂磁通量浮现事件及其后的一系列小尺度高能事件。这些独特的观测清晰地将这些现象联系在一起。利用 SST/CRISP 获得的高分辨率(0."057/像素)磁图,我们能够可靠地测量光球层磁场,并探测到导致后续爆发性大气事件的双极浮现。值得注意的是,这次小尺度浮现事件在较低分辨率的 SDO/HMI 磁图(0."5/像素)中仍然无法分辨。我们报告了 Ca II K 波段中与浮现双极相关的暗泡的出现,这是磁通量浮现模拟中预言的标准膨胀磁穹顶的标志。还发现了重联的证据:首先是通过一个 Ellerman 炸弹(EB),随后是在紫外爆发(UV burst)旁发射的一股喷流。该紫外爆发在日冕 SDO/AIA 通道中表现出微弱的极紫外对应体。通过计算微分发射度(DEM),显示其等离子体温度超过 1 MK,密度介于上色球层和过渡区之间。我们的研究展示了高分辨率磁图在揭示触发 Ellerman 炸弹、紫外爆发和喷流等现象的机制方面的重要性。这可能对最近利用太阳轨道器(Solar Orbiter)在极紫外波段报道的小尺度事件具有启示意义。紫外爆发等离子体温度超过 1 MK 的发现强烈表明我们正在研究类似的特征。因此,我们提示在从全日面磁图得出结论时应保持谨慎,因为这些磁图缺乏揭示其真实磁起源所需的分辨率。

英文摘要:

Advancements in instrumentation have revealed a multitude of small-scale EUV events in the solar atmosphere. Our aim is to employ high-resolution magnetograms to gain a detailed understanding of the magnetic origin of such phenomena. We have used coordinated observations from SST, IRIS, and SDO to analyze an ephemeral magnetic flux emergence episode and the following chain of small-scale energetic events. These unique observations clearly link these phenomena together. The high-resolution (0."057/pixel) magnetograms obtained with SST/CRISP allows us to reliably measure the magnetic field at the photosphere and detect the emerging bipole that causes the subsequent eruptive atmospheric events. Notably, this small-scale emergence episode remains indiscernible in the lower resolution SDO/HMI magnetograms (0."5/pixel). We report the appearance of a dark bubble in Ca II K related to the emerging bipole, a sign of the canonical expanding magnetic dome predicted in flux emergence simulations. Evidences of reconnection are also found: first through an Ellerman bomb, and later by the launch of a surge next to a UV burst. The UV burst exhibits a weak EUV counterpart in the coronal SDO/AIA channels. By calculating DEM, its plasma is shown to reach a temperature beyond 1 MK and have densities between the upper chromosphere and transition region. Our study showcases the importance of high-resolution magnetograms to unveil the mechanisms triggering phenomena such as EBs, UV bursts, and surges. This could hold implications for small-scale events akin to those recently reported in EUV using Solar Orbiter. The finding of temperatures beyond 1 MK in the UV burst plasma strongly suggests that we are examining analogous features. Therefore, we signal caution regarding drawing conclusions from full-disk magnetograms that lack the necessary resolution to reveal their true magnetic origin.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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