Numerous bidirectionally propagating plasma blobs near the reconnection site of a solar eruption^⋆

¹ School of Earth and Space Sciences, Peking University, Beijing 100871, PR China
e-mail: huitian@pku.edu.cn
² Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
³ Space Research and Technology Institute, Bulgarian Academy of Sciences, Acad. Georgy Bonchev Str., Bl. 1, 1113 Sofia, Bulgaria
⁴ School of Physics and Astronomy, Yunnan University, Kunming 650050, PR China
⁵ Indian Institute of Astrophysics, Koramangala II Block, Bangalore 560034, India
⁶ National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100011, PR China
⁷ School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 101408, PR China
⁸ Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences (CAS), Nanjing 210023, PR China

Received: 27 February 2024
Accepted: 27 April 2024

Abstract

A current sheet is a common structure involved in solar eruptions. However, it is observed in a 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 ∼24 min. Using extreme ultraviolet images, we investigated the temporal variation of the blob number around the flare’s 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 ∼1.7 ± 0.5 Mm, ∼79 ± 57 s, ∼191 ± 81 km s⁻¹, ∼10^{6.4 ± 0.1} K, and ∼10^{10.1 ± 0.3} cm⁻³, respectively. The reconnection site rises with a velocity of ≤69 km s⁻¹. The observational results suggest that plasmoid instability plays an important role in the energy-release process of solar eruptions.