Researchers at the Fuxian Lake Solar Observatory of Yunnan Astronomical Observatory, Chinese Academy of Sciences, have made recent advancements in studying the precursor and eruption process of solar dark jets using data from a newly deployed one-meter vacuum solar telescope and other space telescopes. They have delved into the physical mechanisms behind the initial trigger of dark jet eruptions in solar active regions. These findings have been published in the international journal "Astronomy & Astrophysics."
Solar dark jets are among the most spectacular structures in the solar atmosphere, composed of cool and dense plasma suspended within the solar corona. Eruptions of these structures often lead to the formation of solar storms, such as solar flares, coronal mass ejections, and large-scale solar oscillations. Dark jets are a significant topic in solar physics, and there has been no unified answer as to how they become destabilized, leading to intense eruptions. Studying the initial trigger mechanism of solar eruptions not only enhances our understanding of the physical mechanisms behind solar eruptions but also holds crucial importance for predicting solar eruptions.
Multi-Perspective Observations of Filament Eruption Preceding a Filament Channel Eruption
Image courtesy of Yunnan Observatory
Dr. Wang Jincheng from Yunnan Observatory and his collaborators conducted a detailed study of the physical processes leading up to the eruption of the filament channel NOAA 12680 on September 12, 2017, utilizing observational data from the one-meter New Vacuum Solar Telescope, the Solar Dynamics Observatory, and the Solar Terrestrial Relations Observatory. From two observational perspectives, they scrutinized the precursor activities preceding the eruption.
They identified two filament-like jet activities preceding the eruption, both exhibiting characteristics of untwisting motions. Based on these features, researchers inferred that these filament-like jet activities were triggered by magnetic reconnection between the newly emerged magnetic flux and the background open magnetic field, resulting in the release of the filament-confined magnetic field. As the eruption of the filament approached, material was also ejected from the brightening regions associated with the two filament-like jet activities, indicating similar physical processes and the release of the filament-confined magnetic field.
Additionally, researchers found a decrease in the magnetic field strength above the filament, suggesting that the initial phase of the inverted-U-shaped filament involved perturbation or uplift of the filament-confined magnetic field induced by the newly emerged magnetic flux. This perturbed filament-confined magnetic field underwent magnetic reconnection with the background open magnetic field, leading to the release of the filament-confined magnetic field and consequently reducing the magnetic pressure above the filament. When the filament-confined magnetic field weakened to a critical value, the filament with strong twist underwent uplift, leading to the eruption.
