利用大熊湖太阳天文台的全日面Hα蓝翼观测对微型暗条爆发的统计分析
Statistical Analysis of Minifilament Eruptions Using Full-disk H$α$ Blue-wing Observations at Big Bear Solar Observatory
AI总结：
本研究基于大熊湖太阳天文台的Hα蓝翼观测，开发算法检测微型暗条爆发，统计其发生率、长度等特征，分析其空间分布，探讨其对太阳风小尺度结构的潜在作用。
AI中文摘要：
本文利用大熊湖太阳天文台的高时间分辨率全日面Hα蓝翼观测，对微型暗条爆发（MFEs）开展了全面的统计分析。尽管微型暗条爆发对日冕动力学和太阳风结构形成具有公认的重要性，但以往研究常受限于样本量小或视场受限的问题，使得关于其全球发生规律和特征属性的诸多问题尚未得到解答。我们开发了一种结合强度阈值与时间追踪的算法，用于检测Hα蓝翼图像中的突发增强现象。在2020年6月9日的4小时观测期间，共识别出1986个此类事件。这些检测结果通过Hα线心观测进行交叉验证，以确认相关暗条结构的存在。分析得出其发生率约为6.6×10⁴次/天，平均长度约为17 Mm，典型寿命约为21分钟。爆发长度呈现幂律分布（斜率约为-4.8），且持续时间与长度呈亚线性比例关系，表明规模更大的爆发往往持续时间更长。我们还结合活动区邻近度对微型暗条爆发的长度分布进行了分析，结果显示，发生在黑子区域附近的爆发平均长度大于全球平均爆发长度。此外，我们利用爆发密度图分析了微型暗条爆发相对于冕洞边界的空间分布，结果表明冕洞内部的活动受到轻微抑制，而边界区域的爆发频率处于中等水平。我们简要探讨了微型暗条爆发在构建太阳风小尺度特征（如磁开关和小尺度磁通量绳）方面的潜在作用。
英文摘要：
This paper presents a comprehensive statistical analysis of minifilament eruptions (MFEs) using high-cadence full-disk H$α$ blue-wing observations from Big Bear Solar Observatory. Despite the recognized importance of MFEs for coronal dynamics and solar wind structuring, previous efforts were often limited by small sample sizes or restricted fields of view, leaving open questions about their global occurrence and characteristic properties. We developed an algorithm incorporating intensity thresholding and temporal tracking to detect sudden enhancements in H$α$ blue-wing images. A total of 1986 such events were identified during a 4 hr period on 2020 June 9. These detections were cross-validated using H$α$ line-center observations to confirm the presence of associated filament structures. The analysis yields an occurrence rate of $\sim$6.6$\times 10^4$ per day, an average length of $\sim$17 Mm, and a typical lifetime of $\sim$21 minutes. A power-law distribution in eruption lengths (with slope $\sim$-4.8) and a sublinear scaling between duration and length suggest that larger eruptions tend to last longer. The length distribution of MFEs was further analyzed relative to active region proximity, revealing that eruptions occurring nearby a sunspot region were, on average, larger than the global mean eruption length. Additionally, an eruption density map was used to analyze the spatial distribution of MFEs relative to coronal hole boundaries. The results indicate a mild suppression of activity inside coronal holes and intermediate eruption frequency in the boundary regions. We briefly discuss their potential role in structuring the small-scale solar wind features such as magnetic switchbacks and small-scale magnetic flux ropes.
