Sunspot penumbral filaments intruding into a light bridge and the resultant reconnection jets

Abstract

Penumbral filaments and light bridges are prominent structures inside sunspots and are important for understanding the nature of sunspot magnetic fields and magneto-convection underneath. We investigate an interesting event where several penumbral filaments intruded into a sunspot light bridge for more insights into magnetic fields of the sunspot penumbral filament and light bridge, as well as their interaction. The emission, kinematic, and magnetic topology characteristics of the penumbral filaments intruding into the light bridge and the resultant jets are studied. At the west part of the light bridge, the intruding penumbral filaments penetrated into the umbrae on both sides of the light bridge, and two groups of jets were also detected. The jets shared the same projected morphology with the intruding filaments and were accompanied by intermittent footpoint brightenings. Simultaneous spectral imaging observations provide convincing evidences for the presences of magnetic reconnection related heating and bidirectional flows near the jet bases and contribute to measuring vector velocities of the jets. Additionally, nonlinear force-free field extrapolation results reveal strong and highly inclined magnetic fields along the intruding penumbral filaments, consistent well with the results deduced from the vector velocities of the jets. Therefore, we propose that the jets could be caused by magnetic reconnections between emerging fields within the light bridge and the nearly horizontal fields of intruding filaments. They were then ejected outward along the stronger filaments fields. Our study indicates that magnetic reconnection could occur between the penumbral filament fields and emerging fields within light bridge and produce jets along the stronger filament fields. These results further complement the study of magnetic reconnection and dynamic activities within the sunspot.

14 pages, 9 figures, 3 movies, abstract shortened to meet arXiv requirements, accepted for publication in A&A

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Cited by in corpus (4)

• Coronal microjets in quiet-Sun regions observed with the Extreme Ultraviolet Imager onboard Solar Orbiter
• Spectroscopic observations of a flare-related coronal jet
• Statistical Investigation of the Kinematic and Thermal Properties of Supra-arcade Downflows Observed During a Solar Flare
• Various Activities above Sunspot Light Bridges in IRIS Observations: Classification and Comparison