Statistical Analysis of Minifilament Eruptions Using Full-disk H$\alpha$ Blue-wing Observations at Big Bear Solar Observatory

Abstract

This paper presents a comprehensive statistical analysis of minifilament eruptions (MFEs) using high-cadence full-disk H$\alpha$ 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$\alpha$ 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$\alpha$ 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.