Journal Article

Ultra-high-resolution observations of persistent null-point reconnection in the solar corona

Wang, Y. L., Aulanier, G., Xing, C., Verbeeck, C., Li, H. T., Peter, H., Rodriguez, L., Aznar Cuadrado, R., Ding, M. D., Priest, E. R., Zhu, X. S., Cheng, X., Berghmans, D., Barczynski, K., Smith, P. J., Solanki, S. K., Chen, J., Zhukov, A. N., Harra, L., Guo, Y., Long, D., Parenti, S., Chitta, L. P., Teriaca, L.

2023

Overview

Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s −1 and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona. Magnetic reconnection is a fundamental energy release mechanism in space and laboratory plasmas. Here, the authors show persistent magnetic null-point reconnection in the solar corona at a scale of about 390 km.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 639/33/525/870 / 639/766/1960/1134 / Astrophysics / Average velocity / Corona / Eruptions / Extreme ultraviolet radiation / Heat / High resolution / High temperature / High temperature plasmas / Humanities and Social Sciences / Laboratories / Magnetic fields / multidisciplinary / Polarity / Science / Science (multidisciplinary) / Sciences of the Universe / Solar and Stellar Astrophysics / Solar corona / Solar Orbiter (ESA) / Solar physics / Spacecraft / Spine / Sun / Sunspots / Ultraviolet imagery