Numerous Bidirectionally Propagating Plasma Blobs near the Reconnection Site of a Solar Eruption

TL;DR

This study observes numerous plasma blobs propagating bidirectionally along a solar flare current sheet, providing insights into the fine structures involved in solar eruptions and the role of plasmoid instability in energy release.

Contribution

First detailed on-disk observation of multiple plasma blobs in a solar eruption current sheet, analyzing their properties and implications for reconnection physics.

Findings

108 plasma blobs observed propagating bidirectionally

Blob properties include width ~1.7 Mm, velocity ~191 km/s, temperature ~2.5 million K

Reconnection site rises at ≤69 km/s, indicating plasmoid instability's role

Abstract

Current sheet is a common structure involved in solar eruptions. However, it is observed in minority of the events and the physical properties of its fine structures during a solar eruption are rarely investigated. Here, we report an on-disk observation that displays 108 compact, circular or elliptic bright structures, presumably plasma blobs, propagating bidirectionally along a flare current sheet during a period of $\sim$24 minutes. From extreme ultraviolet images, we have investigated the temporal variation of the blob number around the flare peak time. The current sheet connects the flare loops and the erupting filament. The width, duration, projected velocity, temperature, and density of these blobs are $\sim$1.7$\pm$0.5\,Mm, $\sim$79$\pm$57\,s, $\sim$191$\pm$81\,\kms, $\sim$10$^{6.4\pm0.1}$ K, and $\sim$10$^{10.1\pm0.3}$ cm$^{-3}$, respectively. The reconnection site rises with a velocity of $\leqslant$69\,\kms. The observational results suggest that plasmoid instability plays an important role in the energy release process of solar eruptions.