Ultra-high-resolution observations of persistent null-point reconnection in the solar corona
Barczynski, K.; Peter, H.; Chitta, L. P.; Solanki, S. K.; Zhukov, A. N.; Berghmans, D.; Parenti, S.; Rodriguez, L.; Verbeeck, C.; Aulanier, G.; Harra, L.; Cheng, X.; Ding, M. D.; Teriaca, L.; Chen, J.; Guo, Y.; Priest, E. R.; Xing, C.; Aznar Cuadrado, R.; Smith, P. J.; Wang, Y. L.; Long, D.; Zhu, X. S.; Li, H. T.
China, Germany, United Kingdom, France, Norway, Belgium, Russia, Switzerland
Abstract
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.